Friendship is Magic
When she arrives, she debates leaving the package anonymously propped up against the door for him to find. But she has the card wrapped up on the inside and she knows he's been home all day, so she knocks and tries not to smile too much at his surprise.
"Why, Detective Beckett." There's a strand of tinsel falling across his face. Behind him she can see a tree that's probably bigger than her entire apartment. "Bearing gifts, I see. Come in."
He steps aside to let her in, and she enters just in time to hear "sharing kindness is an easy feat, and magic makes it all complete" from the TV.
"Huh," Castle says. "I thought I changed the channel before I opened the door."
"My Little Pony?" Beckett arches one eyebrow, because if she doesn't he'll know what's on her DVR. "Really, Castle?"
"I'll have you know," he says, not the least bit ashamed, "Skylight Sparklebolt is very well respected on all the forums.
"That's the name I use for fanfiction," he adds, when she doesn't so much as blink. "My current epic has excellent reviews. It's really a very moving tale where Twilight Sparkle falls under a terrible curse that causes amnesia and her friends must race against time to make her remember who she is before the curse becomes permanent."
"I see." She chooses not to tell him that ridiculous as the premise is, it still sounds better than anything StormchaserKatie12 ever wrote. Instead she lifts the gift in her hand and shakes it a little. "I brought your Christmas present. But if it's too adult for you I'm sure I could exchange it for a stuffed pony."
"Hey," he says. "Respect the ponies. Can I open it now?"
She's inexplicably nervous as she watches him unwrap it. Carefully, she notes. Huh. She would have figured him for the type to just rip right in. And it's not like she hasn't spent enough time with him to know that he'll like it or to know that he won't care it's nothing extravagant, but—it's still a relief to watch his eyes light up.
"Survival guide for the zombie apocalypse." He nods his approval. "I'll put this in the emergency kit."
"Merry Christmas, Castle." She lets herself smile at him. "I'll see you after Christmas."
He frowns. "I thought your dad wasn't coming until tomorrow."
"Well, no, but—"
"You shouldn't spend Christmas Eve alone," he says. " Alexis and Mother will be home soon. We're making cookies for Santa. You should join us. And don't tell me Santa isn't real. Because he is."
She settles for an eye roll, but she doesn't wrestle with the decision for very long because they both know she wants to stay. "Okay," she agrees. "But only if there's no repeat performance of that Santa dance you did at the precinct yesterday."
He smirks at her in answer. "Deal."