Beckett and Castle are called to investigate the murder of a wealthy woman, killed by a nail gun. Castle went to boarding school with the victim's husband, Damian Westlake (Jason Wiles). While Beckett considers Castle's old friend the prime suspect, Castle disagrees. Their investigation leads them to a cold case: the murder of Damian's father, Philip Westlake, that occurred two decades ago.
- Amicable Exes: Victoria Westlake's business office was on the bottom floor of her ex-husband's brownstone, so she still saw him and got along with him to a point, with them even discussing reconciliation.
- Astonishingly Appropriate Interruption: When Beckett introduces herself to Damian:"Mr. Westlake, I'm Detective Kate— [notices Castle is with him] Castle."
- Awesome Anachronistic Apparel: Victoria's bowtie-wearing jeweler who helps with the case and seems pretty knowledgeable about people replacing jewels with imitations.
- Because You Were Nice to Me: Deconstructed. Damian earned the long-term loyalty of Richard Castle due to his kind treatment of Castle in their teenage years. Damian recognized Castle's writing talent and helped him cultivate his skills, even publishing his story in the school newspaper. However, it becomes clear during the episode that Castle had never noticed Damian's character flaws and was willing to excuse his friend's questionable life choices.
- Broken Pedestal: Castle at the end forsakes Damian, after learning that Damian had orchestrated the murder of his own father.
- Gold Digger: Damian was a male example. He had nearly exhausted his own fortune when he courted a wealthy woman and convinced her to marry him. He spent much of her money and was in search for a replacement.
- Got Me Doing It: While interrogating Hassberg, Beckett briefly imitates his Slavic accent.
- Ignored Epiphany: Damian at one point admits to Beckett that he is a terrible person and has lived "a careless and wasteful life" but didn't kill his wife. While that's true, he doesn't let this realization of his own moral failings lead him to admit the murder he did arrange.
- Inheritance Murder: Damian hired a sociopathic former classmate to kill his father when the man threatened to cut him off.
- Justified Criminal: Damian Westlake claims that stealing his wife's jewelry and replacing it with copies fell under this because he'd been the one to buy her that jewelry and it wouldn't have any remaining sentimental value. Whether or not this resonates though becomes a moot point when compared with his other actions.
- The Mistress: Callie to Damian Westlake.
- Reformed Criminal: Hassberg the carpenter, an early suspect.
- That One Case: Detective Salazar, who investigated the murder of Phillip Westlake, references this.Salazar: I really hated leaving the job with that one still unsolved.
- True Companions: It is implied the reason the detectives were so hard on Damian is because he hurt Castle after discovering how much of a scumbag he is.
- Undying Loyalty: Damien was the first person to encourage Castle, to show faith in him, to tell him he had talent. In return, Castle has unshakeable faith in Damien.Castle: Without him, I'm a lawyer. A grifter. A rodeo clown. I don't know. But I wouldn't be me.
- Verbal Backspace: A suspect points Castle and Esposito to Damian as Victoria's killer because he overheard them arguing, adding that if he were Damian, he would have done so "just to shut her up". He then sheepishly asks Esposito not to include that in his statement.
- What the Hell, Hero?: Beckett chews into Castle for withholding information about Damian and defending him.
- Yandere: Victoria's real murderer is her ex-husband's new girlfriend, who was furious about them getting back together.
