Well, if there's anything I love more than Castle it's The Muppets. So, since we have no Christmas episode this season, here is a crossover for your Christmassy reading. I hope to have it all done and dusted by Christmas Day, but I'm not fantastic at writing to a deadline (this is my 'fun' thing after all), and my plan of writing as much as possible beforehand didn't really work.

I've made a playlist to go along with the fic, mostly just Christmas songs with a couple of Muppet tunes too, which you can find on 8tracks (where I have the same username as here) with the same title as the story.

There's magic in the air this evening, magic in the air.
The world is at her best, you know, when people love and care.

They're already at their second coffee stop of the morning when Beckett guiltily realises someone is missing. "Castle, where's your mom? I thought she was coming with us to do some Christmas shopping today."

He carefully drapes their shopping bags over the spare chair at the table. "Oh, she ran out the door yesterday morning saying something about a 'last-minute favour' and I haven't seen her since. I assume she's fine and not floating down the Hudson."

"Castle."

"What?"

"Not appropriate."

"If she were here, she would laugh."

"Well, she's not." Her phone shrills brightly from the tabletop and she sees Esposito's name and face on the screen. "Beckett." Castle is already handing her a pen and napkin to jot down the address as she tells Esposito to expect them at the crime scene in about thirty minutes, enough time to finish their coffees and find a cab to get from Chelsea over to Broadway. Castle looks at the address as Beckett hangs up and he frowns.

"Is that one of the theatres?" She nods to confirm. "I bet you ten dollars that mother knows someone in the cast of whatever play it is that's being put on there."

Beckett laughs, "I'm not taking that bet, Castle."

"Seems your mom more than knew someone at the theatre, Castle." Ryan looks over to Beckett and Castle they walk through the main doors of the theatre into the lobby, and motions for them to join him.

"Mother, what are you doing here?" Castle puts an arm around her shoulders as she sniffles delicately.

"I had a call from an old friend of an old friend yesterday, a short notice thing, and could I help? Well of course I came straight over, he's the sort you don't say no to."

"Who, Martha?"

The actress allows herself a little dramatic pause before the reveal, how could she not? "Why, Kermit the Frog, of course."

The little group around her stills in surprise, but Rick recovers first. "Kermit... as in... The Muppets?"

"Yes." Martha answers matter of factly. "After all, this is the Muppet Theatre, Richard!"

"Oh." Kate looks at Ryan, who shrugs in response. "Right, well, Castle are you gonna stay with Martha?"

"Oh I'm alright dear, it was just a bit of a shock."

"She found the body," Ryan supplies, and Castle squeezes his mother's shoulders a little tighter with a deep breath of understanding.

Martha puts on a brave face and pats her son's hand. "You all go on and get to work. I'll stay here till you say I can go."

Beckett nods, "We'll need to take your statement, maybe at the precinct? Then I can give you a ride home."

"Alright darling, whatever's easiest for you." Beckett and Ryan head to the crime scene while Castle waves to the nearest officer and asks her to see if she can find a coffee and somewhere to sit that isn't draughty for his mother, much to Martha's consternation, before he follows after the detectives.

"Javier Esposito, if you don't get those rats out of here, so help me I will withhold your Christmas gift!"

"Lanie, I'm trying! But they're upset, okay?" Esposito recoils slightly as he takes a poke to his chest with every point she makes.

"I can't work with them scurrying around, CSU are doing their nut about the crime scene being contaminated, and who knows what time he died and if that head wound was the cause of death or not?"

"Hey guys, what's going on?" Beckett asks as she and Ryan arrive in one of the dressing rooms backstage. Lanie and Esposito turn to the newcomers with identical glares on their faces, and Beckett has to hold in a laugh. She raises her eyebrows at Espo, knowing better than to push Lanie, and he relents.

"The victim is Allan McCormick, seventy-three years old." He holds up a baggy with a New York driving licence. "He was the janitor of the theatre, and has been forever it seems. The rats are a bit upset."

"A bit?!" A squeaky voice with a broad Brooklyn accent interjects. "We're devastated! Allan was our friend, he always shared his biscuits with us."

Castle arrives in time to add the punchline, "And the quickest way to a rat's heart is through his stomach."

"Hey, you're Richard Castle! I've seen all your movies!"

"Uh..." The humans turn as one to face the rat who was so happy to meet his favourite... actor?

"Thanks... Rizzo, right?"

"Yeah, that's me! Boy, it's an honour to meet you!"

"The pleasure's all mine," Castle replies gracefully, and reaches down to shake Rizzo's little paw.

"Guys, can you clear out and let the cops do their jobs please, come on." Everyone turns again and stop in their tracks when they see who is trying to get the grieving rats out of the way.

Esposito is speechless, but Ryan whispers, "Wow, Jenny is never going to believe me when she hears about this later."

"Hi ho, everybody," the tired voice says. Beckett steps forward and introduces herself.

"Mr... uhm, sir? I'm Detective Kate Beckett. I'm very sorry for your loss." The frog nods in acknowledgement. "I have a few questions, is there somewhere more private we could go?"

"Please, call me Kermit. We can go to my office." Beckett gives him a small smile and glances at Ryan.

"Guys, could you speak to the rats please?" Ryan and Esposito both take a deep breath and shrug in unison, clearly not looking forward to the task. Her eyes sparkle with silent laughter as she follows Kermit, her slightly starstruck partner right behind.

Kermit ushers them into his office a few doors down and offers coffee, though Beckett thinks that's borne of an autopilot habit, and she declines. Castle takes her lead, letting her begin on her questions while he roams the edge of the office studying the framed photos on the wall of various celebrities with Kermit and the gang.

Beckett takes a seat and suddenly realises she doesn't even know what time the victim may have died. She shakes her head once before taking a less direct questioning route. "Kermit, could you tell me about what Mr McCormick did for you here in the theatre?"

The frog hums with a nod before he begins, "Sure, he was the janitor. Had been for, oh, so many years I don't even know. He worked at the theatre before we took it over, and that was a couple of decades ago. I'm not even sure that he didn't live here, we never sent his pay check by mail, he just picked it up from the office every week." Kermit sighs. "So many things about him that he never told us and we'll never know."

Beckett gives him a small smile, allowing Castle's footsteps to permeate the silence a little before she continues, "Do you know if he had any family?"

"Oh goodness, yes his brother's son, Jason. He's here quite a lot in the last couple of months, helping Allan out. I don't think there's anyone else of his family left. If he had been married in the past he never mentioned it."

Beckett jots down the name and glances over at Castle, who is still absorbed in looking at the photos. "Just one more question, Kermit. Do you know anyone who might have wanted Mr McCormick dead?"

Kermit stares blankly at the detective for a second before he breaks eye contact and shakes his head. "He was a good man."

She stands and thanks him for his time before nudging Castle's elbow to get his attention before he ends up staying there for hours without realising she's left. As soon as the door closes behind them, he starts talking. "Did you see all those people who've worked with them, Beckett? It's like a who's who of famous people: Elton John, Julie Andrews, the Osbournes, the Obamas, Mark Hamill and Chewbacca and R2-D2 AND C3-PO, oh and did I mention Queen Elizabeth the Second?! The list is almost endless!" He's almost buzzing with excitement and it's all she can do to keep from smiling at his endearing enthusiasm. "But there's almost no authors. They could really do with more. I'd be there in a shot!"

Beckett rolls her eyes but he's too busy gesticulating to notice. "Castle, not sure it's your target market really. Do you want little kids reading about murder?"

The thought sobers him. "But Alexis was eight when she started demanding to proof-read my chapters. And besides, it's Sesame Street that's for little kids. The Muppets are for bigger kids."

"Like you, you mean?"

"Duh."