A/N: I am honestly blown away by the amazing response to this story. I'm truly grateful to know so many are still reading Castle fanfic after all this time. I was curious to see where you all thought I was taking this story, so thank you for sharing your thoughts on those possible paths. All will be revealed – eventually :-P
For clarity, this AU does not include the Slaughter case, and stretches the timeline of the end of 47 Seconds and the Limey.
Disclaimer: Nope, not mine sadly.

Kate Beckett's phone was ringing before she even exited Castle's building, but she knew who would be calling and wasn't interested in talking to either of them. She turned off her phone and shoved it in her back pocket, a plan forming in her mind as she jumped in the first cab she could find and headed back home. She stopped only long enough to throw a few items into a duffel and abandon her phone on the kitchen counter. She collected another set of keys from her entry table and was out the door again within 10 minutes. She didn't look back as she slammed the door.

After unsuccessfully dialing Kate's phone for over 3 hours, Lanie had had enough. She stormed over to her apartment and banged on the door until Kate's neighbor came out and told her Kate obviously wasn't home, and to stop making racket. Lanie apologized, tried a few probing questions about when Kate may have been last seen, but the neighbor was of no help at all, so Lanie gave up and headed home, making one last attempt to contact her friend, and then another call to pass on her lack of success. She determined to visit the precinct the next day and confront Kate about her behavior and explain the afternoon's activities.

Castle wasn't happy to hear Lanie had not been able to contact Kate, but as his calls had also not been answered he wasn't surprised. He agreed to meet at the precinct first thing the next morning so they could sort things out. He decided to turn up with her favorite coffee and bear claw and hope that would be enough for Kate to at least hear them out. He realized it had been weeks since he had bought Kate coffee – weeks since he'd called her Kate, even in his head – and was a little ashamed. That was not how friends behaved, let alone the partners that they had been, and he was determined to make amends.

Lanie and Castle arrived to a near empty bullpen the next morning, with no sign of any of the team. Captain Gates was behind her closed office door, apparently on the phone. Castle was glad, as he wasn't ready for more commentary on his recent behavior. He hoped to get Kate into the break-room before he was seen. He had just placed the coffee and bear claw onto her desk when Lanie approached, having been to the boys' desks.

"I don't think they're here, Castle. Their desks look abandoned – all three of them." Lanie said dejectedly, belatedly remembering she had a few messages on her phone from Javi the previous night. In worrying about her friend, she had totally ignored them. She called them up now and listened while he explained the three days leave the team had received and offered some interesting activities. By his third message, Javi had obviously thought she was ignoring him, because he just said 'see you at the next DB'.

Just as she turned to advise Castle of this, Captain Gates came out of her office and headed straight for them.
"Mr Castle. What are you doing in my precinct?"

"Just delivering breakfast for Detective Beckett, Captain" Castle tried to keep things light, while inwardly cringing at his lame response.

"Well, as you can see, she's not here. So, neither your breakfast nor you are required. Good Day!" It was obviously a dismissal, and she crossed her arms and glared at him, waiting for his withdrawal. He made one more attempt.

"Do you know when she will return? I'd hate for her coffee to go cold, she can get grumpy when she doesn't get enough caffeine." He also tried a light smile, but the narrowing of the captain's eyes told him that was a failure.

"You haven't been delivering her coffee for weeks, Mr Castle, so you may find her caffeine habit has changed. And I am certainly not going to divulge the whereabouts of one of my Detectives to a civilian. If she didn't see fit to inform you," and in this she included Lanie as well, by her sly glance at the ME; "then I will not be breaking her confidence. Now, as neither of you work here, I need you to leave so the rest of us can get back to work."

Castle was still reeling from the verbal slap about his coffee deliveries and wondered how the rest of the team had taken his abandonment – as he could now clearly see that is what his actions amounted to. He wandered dejectedly to the lift, not even noticing when Lanie pressed the call button, then ushered him into it, and gently guided him out on the ground floor. It was only when they were once again outside the precinct that he came back to himself.

"She's running again, isn't she?" Castle asked, though the question was mainly rhetorical.

"Yes, she is very good at that. And if she's thinking what I think she's thinking, then no wonder."

"But why would she …. I mean, she should know ….. I mean, surely…" Castle was dithering, his overactive imagination jumping from one scenario to the next, not liking any of them. He had received a number of shocks in the last 24 hours, upending his view of the world, and he was struggling to regain his balance and calm. He was also starting to feel a deep fear, because he remembered what happened the last time Kate ran, and how long it had taken them to get back into any sort of rhythm. He was really afraid that this time, there was no way back.

"Kate Beckett believes the evidence, and she has had plenty of that in the last two weeks, wouldn't you say?" Lanie turned on Castle, deflecting from her part in recent events. Castle was too much of a gentleman to call her out on it, but certainly Kate finding Lanie in his loft, dressed as she had been, was unfortunate.

"So, what do we do?" Castle asked, truly at a loss for a way forward.
"What we didn't do last time – we find her" Lanie said, already dialing her phone.

A few phone calls later, she had arranged to meet Ryan and Esposito at the precinct that night, once Gates had left for the evening, so Ryan could run a trace on Kate's phone. Meanwhile Espo was surreptitiously checking Kate's bank, knowing Ryan would not approve, and feeling guilty the whole time. Beckett was his boss, and felt like his little sister, but he couldn't deny the desperate worry in Lanie's eyes for her friend. Lanie thought it best if Castle didn't turn up that evening, knowing how the boys felt about him at the moment, so she left his involvement out of her explanation and request for help. Instead Castle cooked dinner for his family, and tried to appear happy and carefree, only belatedly realizing his recent behavior had also impacted his mother and daughter. His guilt and self-loathing grew deeper.

When Ryan identified the last place for Kate's phone as near her home, Lanie rushed over, and rather than banging on the door this time, she used the emergency key Kate had showed her and quietly let herself into the apartment. She found the phone on the counter, and the rest of the place empty and silent. Where ever Kate was, she obviously didn't want to be found. The team only had one more day of leave however, so Lanie decided to let Kate hide, and then to confront her friend the day after. She sent a quick text to Castle to update him, then went home. Once there, she poured herself a large glass of wine and tried again to forget about her part in this latest mess.

Castle, trying to be a good dad, spent the evening with Alexis, and so didn't see Lanie's text until after midnight. His fear settled like a cold weight in the pit of his stomach, and he spent the night staring out his study window, sleep the furthest thing from his mind.