Credit: ABC Photo: Castle Talks to a Perp in 3.15 "The Final Nail"

Castle has a guy friend! His name is Damian Westlake, and he calls Castle “Ricky” to drive home the point that they’re “back in the day” friends. Unfortunately...

Damian’s Wife Got Nailed: Sorry for that, but it’s such a softball. Anywho, Victoria Westlake, interior designer to the rich, was shot in the face with a nail gun in her swanky Manhattan townhouse. There’s also gang tag on the back wall of said townhouse. Surprisingly, Castle is already there when Beckett & Co. arrive on the scene. ("I'm Detective Kate...Castle?" Cute.) The writer is consoling his boarding school friend who just happens to be an unpublished writer. Awkward Tension in A Friendship Alert! Castle gets all offended that Beckett is asking Damian detective-y questions, because people he knows don’t just go around nail gunning their wives. Important thing:  Amber, Vicky’s assistant, says her boss had recently fired a carpenter named Morris who was remodeling the home, because she thought he stole her engagement ring. Also, Morris was near the house the day of the murder and his prints were on the nail gun.  But...

Being A Carpenter, That Last Part Makes Sense: Morris, match in mouth, explains that Vicky just called him over to apologize because she found the ring somewhere else. Silly women and their rings, right? Moments later, we get a really beautiful scene from Nathan Fillion. Castle tearfully tells Beckett that Damian was the first person ever to recognize his writing talent, so he couldn’t possibly be capable of murder. Meanwhile, Beckett says she’s only ever met three people who she’s sure would never kill anyone, which is horribly depressing. Esposito interrupts all of this to say, um, Damian was under investigation at the age of 19 when his father, Phillip Westlake, was murdered in their vacation home in Puerto Rico. Since Castle is only one of two people in the world who thinks this is a coincidence...

Castle Gets Sent Home: After talking with Damian (who predictably says two homicides in one family is just one of those things) and talking with Martha (who insists that her kiddo owes Beckett an apology), Castle emerges from the smoke of the espresso machine and gets back on the case. Having spoken with Vicky’s ex-hubby Simon, who said Vicky was unhappy and thinking of getting back together with him, Beckett thinks Damian’s shady financials might spell trouble. Damian blew through his inheritance and was spending Vic’s money like crazy cakes. Oh, and according to their prenup, if Vicky died, Damian got ten mil. No, Castle insists. It must be someone else, someone like...

Credit: ABC Photo: Alexis Helps Castle in 3

Omar Lincoln, Maybe?: The graffiti artist tried to escape the fuzz on a truck moving ten miles per hour, but alas, he ends up in questioning. Yes, he tagged that wall, but thank goodness, because he overheard Vicky call Damian a thief and tell him she was peacing out. Eek. At the same time, the team finds some questionable stuff on Damian’s credit card statements, stuff that leads them a girl named Callie, whom Damian was seeing on the side. Callie admits that Vicky knew about their relationship and warned Callie that Damian only wanted money and would soon drop her. After Vicky was found dead, Damian was like, “Hey, Callie let’s not mention we were together, k?” And then...

Damian Finally Gets Arrested: And since this precinct only ever keeps one person in holding at a time, Castle can visit him privately to hear his cries of innocence. Damian says that Vicky presented him with divorce papers in an envelope the day of the murder. With the assistance of the helpful mail carrier, Castle figures out that Vicky was still alive when Damian left to play b-ball the day of the murder. Damian’s released, and Beckett becomes convinced he paid someone to do it. But with what money? Meanwhile, with the help of Alexis, Castle decides he’s going to solve that pesky Phillip Westlake murder, so Beckett gets off Damian’s back about it. But Beckett tells Damian...

“Richard Castle Believes In You, and I Believe In Him”: Vicky had recently gotten her engagement ring appraised — the one she accused Morris of stealing —and it ain’t worth much. Twenty-six diamonds worth eight million dollars had been replaced.  Luckily, Damian is able to show Beckett that he hung onto those and didn’t cash them in to hire a nail gun contract killer. And then we all find out that...

Amber Is A Pretty Intense Valentine: In the end, the assistant was just really nuts. Amber was seeing Vicky’s ex-husband, Simon, and got super jeal that Vicky was leaving Damian for her new beau. She just went over there to talk, which is what everyone says after they put the nail gun down. And more bad news...

“Ricky, I...” (Did it): Ironically, Ricky tried to solve Phillip Westlake’s case to help Damian, but that strategy backfired. From a police sketch drawn thirty years ago, Castle is able to instantly identify a weirdo/former classmate named Michael Rutherford, who was seen outside Phillip Westlake’s home. Damian was chummy enough with Michael to ask if he wouldn’t mind killing his dad for him. This is such an upsetting turn of events, Beckett quotes Fitzgerald to Castle, and then they both pull a Hemingway and get a drink together. Oh, you two. Happy Valentine’s Day.