It is Valentine’s Day at the Westlake home but it isn’t coming up chocolate and red roses for Victoria Westlake. Her husband returns home to find her murdered with a dozen nails in her head. Nasty. That certainly is a crime of passion to stand there and face someone with a nail gun. Beckett, Esposito and Ryan arrive at the scene but Castle isn’t answering his phone. Esposito says it is a shame since the society murders are always the freakiest. When they get inside they meet Damien Westlake who is just chatting with an old friend, Castle. Beckett is surprised.

But as they sit down with Damien and Beckett begins her questioning Castle keeps jumping in on his friend’s behalf. You can tell right now there is going to be trouble by the look in Kate’s eyes. And then she lets him have it. “You challenged my authority in front of a suspect.” Castle wants to be on the case and promises to stay out of the way. Somehow I get the feeling he won’t.

So the investigation begins. The team talks to the workers who had been renovating the Westlake home, they speak to the ex husband Simon and Victoria’s employee Amber but the evidence keeps coming back to Damien to Castle’s dismay. Why do you have such an unshakable faith in this man? Beckett asks Castle. When they were in boarding school Damien was the first to tell Castle he had talent and encouraged him to write. “Without Damien I am not a writer, I’m not me without him.”

Beckett discovers that when Damien was a teenager his father was murdered and he was the prime suspect. Beckett jumps down Castle’s throat about hiding information but he said he didn’t know.

They argue loudly and Beckett tells him to go home. It looks bad because Damien inherited his father’s millions upon his death. Castle will need solid evidence to convince him of his friend’s guilt.

He apologizes to Beckett but it will still be hard for him to stay objective. Especially when they discover that Damien’s inheritance is gone and with Vickie dead he stands to inherit her millions. So Castle pushes the team to find other suspects.

They bring in a gang member who was seen near the Westlake house and Kelly a receptionist at a private club whom Damien was having an affair with for questioning. But the testimony circles back to Damien in a bad way.

Castle tries to reason with Beckett. “The man you knew doesn’t exist. He is a character you made up when you were a boy.” Beckett has Damien brought in and arrested.

His wife was going to divorce him and she was the only thing standing between him and millions. You can see Castle wants to crumble as each new story is added to the evidence, but he stands for his friend even so. He finds a way to prove that when Damien left the house that day Victoria was still alive. Alive enough to answer the door and give mail to the post woman.

Has Castle just cleared his friend? Has Beckett arrested an innocent man or is his friend capable of murder? Beckett now attacks the idea that Damien paid someone to off his wife and is determined to find a money trail. Castle likes Simon the ex for the murder and goes off the solve Phillip Westlake’s murder to prove it wasn’t Damien.

Alexis helps Castle go through the old case file on Damian’s father. They find a sketch of a suspicious person found lurking around the vacation home the night of the murder. Castle recognizes the man as another boarding school colleague Michael Rutherford, who was a thief and sociopath back in the day.

Beckett’s money trail runs cold but she discovers that Victoria’s ex husband and her employee Amber were involved with each other despite the fact that Simon said he and Vickie were talking of reconciling. Oh the plot thickens. Beckett sits down with the two love birds and some startling information comes to light. Amber had gone to see Vickie about Simon, begged her to let Amber have him. Victoria said no. Amber didn’t intend to kill her but that ended as soon as she grabbed the nail gun.

So is Damien a free man? Wrongly accused? Castle goes to tell Damien about Amber. But he isn’t done. Michael Rutherford had been arrested for murdering Damien’s father Phillip. He confessed to murder and to the fact that Damien had hired him to kill his father. Castle is cold. “Tell me I haven’t believed in you all this time for nothing.” 

Castle meets with the now-retired detective who worked on the father’s case and explains that he recognizes a sketch in the file as Michael Rutherford, a sociopathic classmate of his and Damian’s who may have robbed the Westlakes’ home and killed the father, and Kate finds that Simon too is broke and is still named in Vicky’s will. Esposito and Ryan find that Simon is now in a relationship with Amber, and Beckett realizes that Amber killed Vicky out of jealousy when Vicky unknowingly confided that she and Simon intended to reunite. Castle tells Damian that the killer has been found and adds that DNA evidence has confirmed Rutherford’s guilt in his father’s murder – but then accuses Damian of hiring Rutherford for the job, which is proven to be true. Damian is arrested and Castle is heartbroken at his misplaced faith in his old friend, and Beckett comforts him before heading off on a Valentine’s Day date with Josh.