A small flying robot was going around Robotropolis. A green shuttle-like robot crossed paths with the robot and another one following it building's side. It approached an entrance to the building while a scout vessel flew by. The robot entered the building and landed on a rotating platform. The platform rapidly declined down a shaft, with a display showing floor numbers. Once it reached 51, a door opens and it drives through. Entering an industrial-like complex, it approaches another shuttle-like robot, this one yellow.
"All secure." Shuttle Robot said and they went their separate ways, with the camera following the yellow one.
Then it entered a hatch.
Nearby, through a shaft, Sonic was rushing along when he stopped and looked back and whispered loudly.
"Come on! Come on! Get the old legsky out guys." he whispered loudly and Knuckles, Antoine and Cat slowly caught up to, out of breath. "I'm waiting!" she said and looked out a vent beside him and saw the green robot from earlier come. "Chill! Swatbot!"
They stood to the side as the vent opened. Using its arm, the bot shone a light into the shaft and looked around. After some time, the Swatbot stopped and opened its main glass compartment, revealing Sally.
"Hi guys." Sally said and Sonic looked over as she left the robot.
"Bout time, Sal. You ready?" he said.
"Ready!" she said.
"Okay guys, let's do to it. Cat, Antoine, you guys cover our backs. Any bots show up, give us the signal. Any questions?"
"Yes, I have a question. What if..." Antoine started but was interrupted by Sonic and left the shaft.
"Cool." he said and Sonic then Knuckles dropped down to beside Sally. "I'm outta here. Let's lock-and-load Sal." he said and they walked away from the area with Cat and Antoine watching from the vent.
"Bon voyage!" Antoine said.
"Good luck!" Cat said.
Sally, Sonic and Knuckles were now back in the industrial area walk on-top of a ramp-like contraption. Above them was a large plane. Sally opened up a hatch on it, with Sonic boosting her up into it. The fuselage was full of electronics. Sonic and Knuckles were still outside, while they watched in Sally working.
"Whoa." Knuckles said.
"Man, what is all this stuff?" Sonic said.
"It's the brains of the plan." Sally said.
"And you're gonna do a little brain surgery, right?"
"More or less. First I have to break the access code, get into Robotnik's mainframe computer, and reprogram the launch data." she said and took NICOLE from one of her boots and continued to work.
"Then kaboom, these stealth butts are luncheon, yes?" Sonic asked.
"They're luncheon, yes." she said and put NICOLE, into a slot on the station she's working with. "NICOLE."
"Ready, Sally." NICOLE said.
"Access main database."
"Run decoding program for X."
Then a holographic display appeared with a grid. Numerous password combinations appeared as NICOLE tried to determine it. then it stopped on Meteor. Sally looked at the display closely as Sonic, tapped his hands on the metal frame of the fuselage impatiently while Knuckles leaned on the top.
"Sonic, do you mind?" she said.
"Not very well. Dogs mind, not hedgehogs." he said.
"Well show a little patience."
"Hey, hey, hey, patients are for hospitals. We're in robo-country, and that makes me itchy." he said and looked out from the fuselage and saw two shuttle-like bots roaming around. "Whoa, hurry it up, Sal. Party-crashers coming."
"Incoming message." NICOLE said and a message came up on the holographic display: Bean.
"Bean?" Sonic and Knuckles said.
"Oh my gosh, Sonic, Knuckles, my father called me Bean when I was little. NICOLE, give me message origin." Sally said.
Sonic and Knuckles looked outside again and saw one of the bots still roaming around and starting to come toward them.
"Sal! We gotta put the pedal-to-the-metal!" he said.
"I have to check this out. It may be from my father!"
"Well hurry up!" Knuckles said.
"Message origin: Area 12, Sector 9, Quadrant 32." NICOLE said and the holographic display showed a map of the Dark Swamp.
"The Dark Swamp?!"
The bots got closer. One passed Sally's abandoned bot and looked curiously. In the shaft itself, Antoine and Cat standard at guard while the bot looked through the vent and eventually left, prompting Antoine to give off a sigh of relief.
"What is taking them from so long?" he asked.
"Those computers can be tricky." Cat said. "Relax, Antoine."
"Relax? Yes! Yes! A very good ide..." Antoine started while he leaned on the vent causing it to open and him to fall out.
Then he landed at the feet of the bot that was checking the vent.
Then it started firing lasers at him as he ran for cover back into the shaft, screaming all the way. Some of the shots entered the shaft, causing both Cat and Antoine to run deeper into the shaft.
"Oh man, Ant did it again! Look Sal, when I juice, jam for the air duct. I'll meet you at the usual place." Sonic said.
"I'll go with him." Knuckles said.
"Be careful, guys." Sally said and they left from the fuselage and landed on the ground.
They looked at the two bots and ran at them.
"Yo, Swatbutts." Sonic said and they started firing their lasers at them as they dodged them easily. "How about a little laser tag?" he asked and passed by the bots to the side, making them chase after him.
Once they were gone, Sally ran toward the vent and was helped up by Cat and Antoine.
The bots continued to fire at them, missing every shot. More bots had joined, but Sonic and Knuckles responded to this by weaving between all of them, causing confusion. In the shaft, Cat, Antoine and Sally were making their way through it. Sonic and Knuckles' continuous swerving and punching had made the bots confused.
"Yo, Swatbutts, aren't you looking for us?" Knuckles asked.
"We're the only ones around!" Sonic said.
The bots broke out of their confusion and fired at them, who were on a pile of scrap metal. They dodged it by hopping backwards and into the shaft. The bots continued to fire but missed as Sonic rushed and Knuckles glide after the rest of the group.
Reaching a T-intersection, Antoine and Sally ran left, but Cat stopped and looked back, seeing one of the bots from earlier approaching.
"Here comes trouble!" he said and walked off to the right as the bot entered the intersection.
It went after Cat to the right.
In a dank area outside Robotropolis, Antoine and Sally approached an aged wall. Then sat on an old pipe as Antoine let out a sigh.
"It's Sonic and Knuckles!" Sally said as Sonic zipped over the two and ran back, approaching Antoine in anger with Knuckles next to him.
"What happened, Antoine?" he asked angry.
"Yeah, you could've gotten us hit!" Knuckles said angry to.
"It was not my fault. Cat said I should relax, and I leaned against the..." Antoine stated but was cut off.
"...yo! Where's Cat?" Sonic said.
"Yeah, where is he?" Knuckles asked looking around.
"He was right behind us in the tunnel a-and then we lost him." Sally said
"Swatbots must've busted him. I'm juicing back." Sonic said and went to run off, but Sally stopped him.
"Sonic, I'm sure that message was from my father. I'm going to the Dark Swamp and find him. Antoine can come with me." Sally said.
"Antoine?!" Sonic and Knuckles said in shock.
"You're kidding, riiight?" Sonic asked.
"Wrong?" Knuckles said confused.
"Right or wrong?" Sonic asked.
"I'm right you're wrong. As usual."
"Excuse me while I chunk my breakfast." he said holding onto his stomach.
"Same here." Knuckles said holding his stomach to.
"Whatever. Come on, Antoine."
"Yo, Sal." Sonic said and ran up to Sally and Antoine. "Soon as I find Cat, I'll blast for the swamp. Be mondo careful."
"You too, Sonic."
"Gotta juice it loose!" he said and charged up then rushed away in a trail of fire.
"Wait for me!" Knuckles said and ran, jumped and started gliding with him.
In Robotropolis Robotnik was in his lair, then lowered his chair in his control room while Snively slowly walked up behind him.
"Tell me Snively, how did the hedgehog get past all my security?" Robotnik said.
"Through an air duct, Dr. Robotnik." Snively said.
"An air duct?"
"Then seal it off!"
"Yes, sir. One more thing, sir, we captured a Freedom Fighter."
"Well, that's good. That's very dang good, Snively." Robotnik said and turned his chair to face Snively. "Where is he?" he asked and Snively pointed beyond him.
"Bring in the prisoner!"
Robotnik turned his chair again as two of the bots from earlier dragged Cat into the room. Cat struggled to escape, despite having a restraint on.
Then a thunderstorm started in Robotropolis, lightning stroked near Robotnik's lair.
"Tell me where Knothole is, old boy, and you have my word that you will not be...robotasized." he said with Cat bound to a chair near.
"I'm not telling you nothing about nothing, Robotnik!" Cat said.
"Ooh, I wouldn't be so sure about that, old boy. I have machines of all kinds, marvelous machines, that can do things you would not believe." he said and Cat gulped.
Meanwhile Sonic zoomed into Robotropolis, going through the streets with Knuckles gliding behind him. They eventually stopped at a side of a trench as a shuttle-like Swatbot flew by and Knuckles went to the ground. Then they ducked and the bot flew by, not noticing them. Then they chased to the bot as it flew away and entered a building and stopped, deploying a ramp. A Swatbot and Cat left the shuttle. Sonic and Knuckles, hid from cover behind a building support and watched on then saw the Swatbot escort Cat into an elevator.
"Hang in, Cat." Sonic said and they looked around then rushed at the elevator, but the door had closed.
Knuckles punched it hard but it didn't work.
"Damnit!" he said and looked at Sonic. "Give a Spin Dash a shot."
Sonic nodded and went into a Spin Dash and wedged himself into the door, causing it to open and they stopped then looked up at the elevator shaft. They walked back, Sonic charged up and ran up the shaft, leaving a trail of fire with Knuckles behind him. As they continued up, they saw another elevator coming their way and Sonic quickly Spin Dashed into the nearest door, wedging it open. They looked around and saw Cat in a jail cell asleep on a bench.
"Psst! Cat! You alright?" Sonic asked and Cat woke up then walked over to them.
"Robotnik's surveillance picked up Sally. He knows she's headed for the Dark Swamp. You gotta save her!" Cat said.
"But, what about you?" Knuckles asked.
"It doesn't matter."
Then a laser blast narrowly missed Sonic and Knuckles, who ducked while Cat went back to his bench.
"Go, Sonic! Knuckles! Go!" he said
Sonic and Knuckles gasped as they ran off dodging laser fire.
"Not to worry, Cat, we'll be back!" Knuckles said and they rushed away into the elevator shaft.
In the Dark Swamp, a spybot hovered around as Sally and Antoine walked around in knee-deep water.
"How much more farther, my Princess? Hmm?" he asked.
"We'll know when we get there, Antoine." Sally said and stopped, making Antoine bumped into her back.
They both shrieked and Sally sighed once she saw it was Antoine, but Antoine had jumped onto a tree branch, still shaking from fear.
"Antoine, what's wrong?" Sally asked.
"A t-t-thousand pardons, my Princess." Antoine said.
"Are you alright? You're trembling."
"Not trembling, my Princess...um...uh...shivering. Yes! I must have catch them...ah, you say *Sneeze* Uh...ah! a terrible cold! Um, I think we should return to Knothole."
"No, Antoine. My father is alive, I know it, and I'm gonna find him." she said and started to walk away.
"But we're having no idea where he is."
Sally stopped and took out NICOLE.
"NICOLE, is there any kind of structure in the Dark Swamp?" she asked.
"Searching..." NICOLE said and a spherical hologram appeared over her, a castle-like structure was shown. "One structure. Ironlock Prison. Schematic display."
"Ironlock Prison?! Oh no! Come on Antoine!" Sally said, put away NICOLE and continued on.
"B-But Princess, wait!" he said fumbling in the tree, caused the branch to break, forcing him to fall.
Sonic and Knuckles were approaching the Dark Swamp, stopped at a cliff-edge overlooking the swamp and heard mosquitoes.
"Oh man, I hate swamps." he said and hit his head in an attempt to kill the mosquito.
"Same here." Knuckles said and tried to kill one to.
"They're full of bugs and junk. Juice time!" Sonic said then they charged up and continued on into the swamp.
Then they stopped at a point laden with scrap metal.
"SALLY!" Sonic said and they listened, but didn't hear anything. "Bummer. Whoa..." he said and looked down and saw two sets of footprints. "Yeah! Now we're getting somewhere!"
"Awesome!" Knuckles said and they went to follow the footprints, with Robotnik's spybot looking on from above.
The video feed was being shown to Robotnik and Snively in Robotnik's lair.
"Doctor Robotnik! We have the hedgehog and his friend! They're in the Dark Swamp." Snively said.
"They're looking for the Princess. A possible double-header. Launch the stealthbots!" Robotnik said.
"Yes, sir." Snively said and pressed a button on his control panel.
In another room, klaxons and lights went off as the stealthbots got ready to launch. A door opened above them.
Back in the Dark Swamp, Sonic and Knuckles continued to follow the footprints with the spybot following.
In Robotropolis, a stealthbot flew up from the doorway that opened and launched away at high-speed.
Sally and Antoine were still walking along to the prison, in knee-deep water again.
"How much farther, my Princess?" Antoine asked.
"Any minute, Antoine." Sally said and they approached some foliage, which Sally moved aside and enters.
"Sacre bleu! Is that..."
Then they looked up at the old and dilapidated rock building. Sally brought out NICOLE.
"NICOLE, give me all data on Iron lock." Sally said.
"Searching, Sally. Built in 1543, abandoned 100 years ago. No other data." NICOLE said.
Elsewhere Sonic and Knuckles continued to follow the footprints at fast pace. Going over the water, the stealthbot arrived when they saw it and Sonic increased his speed and Knuckles glided to keep up. Two lights blinked on the stealthbot and it fired a missile at them.
"Whoa!" Sonic said and looked up to see the missile coming right for them.
"Hedgehog missile alert! Hitting warp seven!"
"Oh great." Knuckles said.
As the missile approached, Sonic increased his speed even more with Knuckles now running with him.
The stealthbot moved ahead and went above a hollow dead tree. Then they looked ahead and Sonic snapped his fingers.
"Time to dust one stealthbot." he said and sped ahead into the tree and went up it, with the missile following him in it.
Then he hopped out and landed on a branch as the missile continued upwards, slamming into the stealthbot, causing it to explode.
Meanwhile Sally and Antoine approached Iron lock at an old bridge. Antoine whimpered. As they started crossing the bridge, it started creaking and moved unsettlingly, forcing them to slow down.
"I'm thinking this is not safe..." Antoine said.
"Don't be such a worrywart, Antoine." Sally said as the bridge started to move more, almost looking like it's about to give way.
Then it settled down in a lower arc position and Antoine held onto Sally.
"Are you alright, my Princess?" Antoine asked.
"Yeah, I'm fine." Sally said gasping for air..
Then they kept walking along the bridge slowly, it continued to move in an unsettling manner. Then it started to vibrate more, causing them to lose their balance and panic.
"Run Princess, run!" Antoine said and grabbed her as they dashed for the end of the bridge.
Then it gave out and fell into a deep chasm as they reached the end, holding onto a cliff edge for their lives.
"Come on Antoine, that's right." Antoine said getting himself up then grabbed Sally's hands. "Come on Sally!" he said and helped her up.
Once they were up, they looked at the menacing structure again. The walls, from their vantage point, were tall. They walked on toward the entrance.
"Princess, I am hating to be such a, um, how you say...uh, err...such a worry-worm, but this terrible place, it's not so good for our health. I am thinking this is so... " Antoine started then kissed her hand. "We go home, yes?"
"We go home, no, Antoine. If my father is in there, I'm going to find him. Is that clear?" she said.
Antoine shook his head, then nodded his head.
"Oui, oui, my Princess, very clear, very clear. But..." he started.
"No 'buts', Antoine. Now let's go." she said and saw Antoine scared. "Antoine!"
Then Antoine jumped and ran after her as she entered the prison.
"Oui, oui, Princess! Here I am! I'm right behind you Princess." he said and kept his distance as they passed the entrance.
"That's comforting..." Sally said and they kept going, Antoine scared.
Meanwhile Sonic was still following Sally and Antoine's path, going over a river passed by the footprints, but came back to them.
"Right behind ya, Sal!" he said and followed the footprints again.
In the prison, Sally and Antoine passed through a jail block and Antoine yelped.
"My Princess, maybe I'm thinking we should..." Antoine started but was cut off.
"Antoine! Look!" Sally said and they ran over to a piece of red fabric on the ground and picked it up.
"What is it?" Antoine asked.
"It's from my father's cloak. I recognize the design. He was here..." she said and held the fabric close, Antoine walked up to comfort her. "Come on!" she said and continued.
As they pass a wooden door, a gust of wind entered the hall, closing it. Antoine jumped from the noise and hopped into Sally's arms.
"Heh-heh-heh-heh, 'ello. It was just a clever way to get into your arms, my Princess." he said.
Meanwhile Sonic and Knuckles arrived at the castle and looked up at it.
"Whoa." Knuckles said.
"Mondo spooky." Sonic said then they rushed at the moat surrounding the castle and jumped over it, making it to the entrance.
"It be a little easier if Tails was here." Knuckles said and jumped over it to. "Then he'd be able to just carry us in."
"Yeah but he's not old enough. And I don't want him to get hurt carryin' us."
Knuckles shrugged and nodded.
Meanwhile Sally and Antoine opened a door, entering a dark room.
"Antoine, my father was in here." Sally said.
"This is good, yes?" Antoine said.
Then a hand reached out and grabbed him from behind. He jumped and flew upwards. Sally gasped and saw Sonic and Knuckles, at the doorway. They looked up at Antoine who was on top of a wall partition.
"Hey Ant!" Knuckles said.
"What are you doing up there, Ant?" Sonic asked.
"Sonic. Knuckles." Sally said.
"What's up, Sal?" Sonic asked.
"Look what I found." she said then pressed a few buttons on NICOLE and acknowledged a computer in the room.
"A computer, so?" Knuckles said.
"My father must've sent me those messages from this computer."
"Looks real ancient. Does it work?" Sonic asked.
"I don't know." she said and pressed a few buttons on the computer. "Keep your fingers crossed." she continued and it activated. "Yes!"
"Access code, please." Computer said.
"Try: Bean." she said.
"Standby for message. Bean, check SUB-TER file (?). End of message." the computer said.
"That's definitely from my father. Somehow he knew I'd find it." she said.
"Fantastique! What does it mean?" Antoine said.
"He didn't finish the message. But at least, now, I know he's alive, I-I just don't know where!" she said and went back to the computer. "Computer, access SUB-TER file."
"Checking: SUB-TER file." the computer said and the screen showed a map.
"Guys, look at this! Do you know what these maps do? They give us access to all of Robotropolis!" Sally said.
"Check out the tunnels! Man, I didn't know they existed." Sonic said pointing at a part of the map.
"Me neither." Knuckles said looking at them.
Then she took out NICOLE.
"Ready, Sally." NICOLE said."
"Access main database." Sally said.
Sonic leaned against a wall and tapped his fingers impatiently. Then he looked at his watch and Knuckles snickered at that.
"NICOLE, get the ole' data out." Sonic said.
"Access granted." NICOLE said.
"Transfer to holographic disk." Sally said.
A loose rock above Sonic fell off the wall and landed on the computer, causing it to malfunction. Suddenly, the whole room started shaking.
"Hey! What's going on?!" Knuckles said and the floor opened up underneath them and they fell into a cavern with water and mud.
"Oh terrible! What happened?" Antoine asked.
"That dumb cell was booby-trapped, that's what happened." Sonic said.
"But what is this place?" Antoine asked while Sonic and Knuckles stood up and covered in mud.
"Eww, whatever it is, it sure stinks." Knuckles said.
Sally walked over to Antoine, Sonic and Knuckles. Then Sonic heard some creaking, causing him to gasp and look down the cavern to see a red light.
"Okay, you guys. Hang here, we're gonna scope out that red light." he said then he and Knuckles charged up and rushed along the cavern, slinging mud back at Antoine.
Antoine wiped it off. After some waiting, Sonic and Knuckles returned, slinging more mud at Antoine.
"Sonic, Knuckles, are you okay?" Sally asked.
"Wherever we go, we can't go that way!" Sonic said.
"Why not?" Antoine asked then the ground shook as a large slug-like one-eyed monster emerged.
"That's why!" Knuckles said.
"Oh my gosh! What is it?!" Sally said.
"Someone you never want to marry." Sonic said and the monster screamed. "Plus, he's in a bad mood."
"But that's our only way out!" Sally said.
"What, what, what, what, what are we gonna do?" Antoine asked.
"Can you dig us a whole?" Sally asked looking at Knuckles.
"Sorry Sal but it's too deep." Knuckles said.
"Ask about his mother! Maybe he's not such a bad guy!" Sonic said and they backed to a wall as the monster lurched toward them. "Nooo, he's ridin' to the core! I've got an idea." he said and pointed to his backpack. "Sal, grab the power ring. Okay, when I hold up my hand, slap it in."
Sally reached into the backpack and grabbed the power ring, but kept her hand in the pack and Antoine did the same.
"Got it." she said.
"Juice time! Hold on!" he said and charged up as he raced at the monster with Knuckles, Antoine and Sally in tow.
The monster sped up and ran at the quartet. Sonic held up his hand and Sally passed the power ring. Using the ring, Sonic charged up increased in speed.
"Whoaaaa!" Knuckles, Sally and Antoine said as they dashed right into the monster's mouth.
It looked ill as its tail extended exploded, revealing machinery. Sonic, Knuckles, Antoine and Sally landed behind the monster.
"Chill guys, everything's cool." Sonic said.
They walked over to the monster, sparking from all the broken machinery.
"Sonic, how did you know it was robotic?" Sally asked.
"The hedgehog knows." he said.
"But now I am thinking we have another problem, hmm? How do we get the hecks out of here?" Antoine asked.
Behind the group was a fork in the cavern. Sally took out NICOLE.
"NICOLE, bring up 'Bean'." she said and a holographic display of the map appeared.
Sally looked at it as Sonic tapped his feet impatiently.
"I'm waaitiing." he said.
"I've got a great idea! We'll take that tunnel!" Sally said and pointed at a pathway in the tunnel system on the map.
The quartet traveled through the cavern system and stopped after entering a clearing and looked around an immense cave with many rock formations.
"Whoa, way cool." Sonic said.
"Where are we?" Knuckles asked looking around.
"According to those maps, we should be very close." Sally said.
"To what?" Antoine asked.
"You'll see. Follow that light source." she said and pointed at a bright yellow light on the other side of the cave.
In Robotropolis, a yellow shuttle-like bot traveled along. Nearby, hidden behind a rock formation, Sally, Antoine, Knuckles and Sonic poked their heads out.
"Let's go." Sally said and they left the formation and tread slowly.
Then they approached a ramp-like object that was holding a stealthbot, and Sonic helped Sally up on. Then she did some modifications to the stealthbot and they continued on in the area making modifications to other stealthbots. She gave the thumbs-up to Sonic after she's done the last one.
"Done. That's the last one. These stealthbots are history!" she said.
"We got one more thing to do. Meet you guys at the usual, gotta juice!" he said and rushed away into a corridor with Knuckles behind him, making numerous stops on his journey to find his way at various intersections.
When they got to Cat's cell he looked in, but it was empty.
"Oh my god." Knuckles said.
"Cat?" Sonic said and held back a tear, and were narrowly hit by a laser blast again.
They looked over to see Swatbots entering so dashed away as the Swatbots continued to fire their laser cannons.
In Robotnik's command center, a siren went off.
"Intruder alert. Detention building. Intruder alert." computer said so Robotnik looked at a display and saw Sonic and Knuckles zipping through a rocky area.
"Consider yourself terminated, hedgehog, echidna." he said and pressed a button on his chair, activating a series of doors for the stealthbots.
Outside Robotropolis, Sonic and Knuckles had met up with Sally and Antoine, as the stealthbots prepared to launch.
"He's launching the stealhbots." Sonic said and searched his backpack and brought out the spybot that was spying on them earlier. "News at eleven." he said and aimed the bot toward Robotropolis as the stealthbots reached the sky.
Robotnik looked at the main monitor and saw a video feed of the stealthbots in formation.
"What is this?! Snively? Recall them!" he said.
"Yes, sir." Snively said and pressed a button the main console.
One of the stealthbots exploded in a fireworks-style, followed by the remaining three. The video feed ended, replaced by a video of Sonic.
"Yo, Robuttnik, that was for Cat. Ah ha ha ha!" Sonic said.
"EAARGH!" Robotnik yelled.