A/N : This story takes place sometime in Season 3 before the finale since I included Captain Montgomery. There may or may not be a little interest between two characters from each team. ;) Hope you enjoy it!

*At the 12th Precinct, New York*

Richard Castle walks into the precinct holding a takeout of two coffees and sees Kate Beckett sitting at her desk staring into space.

"Thinking about me?"

"Of course, why wouldn't I?" Beckett smiles back sarcastically as he hands her a cup of coffee.

"So what case do we have this time?'

"We don't—"Just then, Beckett's phone rings.

"We do now" Castle smiles.

"Beckett. Mmhmm. We'll be right there" She puts down her phone and takes her badge and gun from the drawer, " We got a body at an apartment in Oak Street."

*At the Behavourial Analysis Unit, Quantico, Virginia*

Technical Analyst Penelope Garcia walks past SSA Jennifer 'JJ' Jareau and SSA Emily Prentiss who is busy talking and SSA Spencer Reid who is sitting at his desk reading.

"My fellow crusaders, we have a case" Garcia says as she walks towards the round table room. JJ, Prentiss and Reid gets up and follow.

In the round table room, SSA Aaron Hotcher, SSA Derek Morgan and SSA David Rossi are already seated at the table.

"Alright, we have a dead body in New York City. His name is Elliot McCoy, 28" Garcia says as she switches on the screen revealing the crime scene photos.

"I remember this MO" Morgan says "It was 3 years ago. We caught the killer, I booked him myself."

"Yes, and that is why we are asked to assist the NYPD in this case." Hotchner says. "Wheels up in 30."

*At the crime scene*

Castle and Beckett walks into the apartment and sees the place messed up.

"Someone was looking for something." Beckett says.

They walked into the living room and sees the body of a young man with an acoustic guitar smashed on his head and left at his neck, sitting on the couch.

"Woah. This gives a new meaning to rock 'n' roll" Castle says in awe.

"Rock on, he shall" Javier Esposito says as he walks in.

"What do we have on this guy?" Beckett asks.

"Vic's name is Elliot McCoy, 28. He's a part time musician at the local bar downstairs. The landlady confirmed it." Esposito answered.

"Lives by the guitar, dies by the guitar." Castle adds. Beckett raises her eyebrow.

Beckett turns to Lanie Parish who is examining the body, "Cause of death?"

Lanie was about to answer her but Castle interrupts, " A heavy blow to the head."

"It looks like it for now." Lanie says "But I can't be sure until I fully examine the body."

Just then, Beckett looks up to see a group of people who look like the feds approaching the apartment.

"The suits are here" Castle comments. Beckett walks towards them.

"Agent Hotchner from the BAU department of FBI" Hotch introduces himself, showing his badge.

"And just why is the FBI at my crime scene?" Beckett asks

"I called them" a voice answers.