The Doctor opened the door to the Tardis, looked around, and adjusted his bowtie. Rory and Amy Pond followed him outside, squinting into a densely tangled, humid forest.
20 minutes earlier (which could have been 5000 years in the future), The Doctor had been excitedly telling them that he wanted to take them to a planet where there were dinosaurs made out of chocolate, that were quite amiable to being bitten on as they grazed. Half-way though telling them about this wondrous planet (which they couldn't quite believe, although they had seen odder things while traveling with The Doctor), he slapped his forehead, yelled "OF COURSE", and started zinging and popping away on the control panel of the TARDIS.
And now they had just landed, and they were following him out.
"Uh, Doctor..." Rory said, which seemed to be a way he begin many of his sentences. "Is this the Chocolate Dinosaur planet?"
"Oh, no, totally wrong epoch, wrong galaxy, but we will get back there soon. No, this is business, not pleasure."
The Doctor got down on his knees and peered into the underbrush. Amy looked down at him, wondering how he managed to spend so much time grubbing around, and still keeping his suit immaculate. His bowtie never seemed to get out of place.
"And what are we trying to find here? Where and when are we, even?"
"Oh, I think the 88th Century. Maybe the 89th? I never could keep them straight, one of those two when people started growing a third arm for fashion. This planet was settled by humans and then abandoned, for whatever reason."
"So...what are we doing here?"
"Well, I just realized that I have been going around the problem all wrong. The Silence and The Weeping Angels...two of my biggest enemies of late, and they are hard to deal with because they have...perceptual problems."
Amy and Rory nodded, nervously looking around at the deep forest.
"I've been too parochial about the whole thing. You would think that after a thousand years, I would be over some of my prejudices. The Silence have to be seen to be remembered, and the Weeping Angels can't move when they are being viewed. But even though I have a bit more senses than a human, I still have a basically visual paradigm. But not all creatures do."
While he was explaining this, he had crawled deep into the underbrush, and would occasionally make clucking noises with his tongue.
"But what if we had a creature who perceived not just with its eyes, but with its ears, and even could detect the slightest vibration in the atmosphere?"
"What if?" Rory replied.
"They would still be perceiving The Silence, or The Weeping Angels, even if they weren't looking at them. Even if they were hundreds of feet away. But there is more."
"There is always more." Amy said, gazing into the distance, wondering what type of predators inhabited this jungle.
"There are a few predators so perceptive of their environment, that there situational awareness becomes a sense in itself. They don't need to 'remember' like we do, because to them, their perception and their memory are seamlessly tied together." The Doctor's voice became more muffled, and Amy and Rory were starting to worry that the thicket that he had crawled into was bigger on the inside.
"Oh, and also, just to top it off, this predator has a low level perception filter, it can't be seen unless it wants to. And it can sonically hypnotize humanoids into doing its bidding."
"So...your solution to fighting The Silence and The Weeping Angels is to find a super predator that can sense where anything is, and turn invisible, and control our minds?" Amy asks.
"Makes perfect sense." Rory said, swallowing.
"Aren't you worried that this could be a threat?"
The Doctor suddenly popped out of the bushes on the other opposite side of the clearing, holding in his hands what was a large, exotically striped, but otherwise fairly normal looking terran housecat.
"That is a cat." Rory said.
"Very perceptive of you." The Doctor said, the cat batting at his bowtie.
"So this super-predator...our defense against the universe's most vicious aliens is..."
"He seems to like you." Amy said, smiling in spite of herself. "How did you find him."
"Oh, I asked him. I speak cat."
"Of course you speak cat." Rory said, wondering if there was still time "Today" to go see some chocolate dinosaurs.