An unidentifiable figure snaps a photo of a dead body on a bed inside a ransacked apartment. Castle and Beckett's conversation about a plan to get married on a roller coaster gets put on hold to investigate the murder. The victim is Peter Cordero. He was a Wall Street trader who got shot in the chest. A woman called in the crime from the payphone down the block. Security cameras catch an image of this mystery lady. The victim's cousin, Maria, doesn't recognize her. She says Peter never forgot where he came from, which is Venezuela. She says her cousin was stressed due to something that happened at work recently.
Jamie Berman, head of the JPHarding investment firm, says the victim was his best commodities trader. He recalls Peter hanging with a guy who looked like a gang member. Lanie finds numbers written on the victim's hands and evidence that he was wearing a wire. He was working as an informant for the U.S. Attorney's office. The woman in the photo was his contact. Castle recognizes her when she walks into the precinct. She's Assistant U.S. Attorney Stephanie Goldmark. Captain Gates recognizes the woman by her side. She's U.S. Attorney Elizabeth Weston. She happens to be Captain Gates' estranged sister.
Elizabeth instructed her colleague to make the 911 call anonymously so they wouldn't compromise their case. The U.S. Attorney's office believes the killer took the wire Peter was wearing because it held something incriminating. Elizabeth says Jamie Berman is the target of their investigation. The victim had a one-on-one meeting with the big boss the day he was killed. Elizabeth asks her sis to keep her in the loop regarding the investigation. There's obvious tension between these two.
Jamie Berman is less-than-forthcoming when asked about a heated argument he had with the victim. His questioning is cut short when Berman's colleague pulls this big boss away for a conference call. Back at the precinct, the team learns that the gun used to kill the victim matches one used by a gang member in a robbery. The suspect's photo matches a sketch of the guy Jamie Berman saw with Peter. The gangbanger is named Hector Nunez. The victim's cousin says he used to be Peter's friend. Ties were severed when Hector joined a gang.
Hector Nunez is surprised and upset to learn that Peter is dead. He gave him his gun for protection. Peter was involved in a big, dangerous deal involving bank accounts and transfers. Hector kept record of the account number. It matches the one that was written on Peter's hand. A secret $25 million was transferred. Captain Gates calls on her sister. She wants access to the wire recordings. This leads to a heated conversation between the two involving ambition and following the law. Captain Gates later looks at an old photo of her and her sis in happier times. It's obvious she misses their closeness.
Esposito and Ryan learn from the wire recordings that the victim was dealing with someone named Armando Garcia. The connection may be Peter's original home of Venezuela. Castle and Beckett learn that Armando Garcia is Peter Cordero's birth name. The victim was sending the money to himself. He was looking to disappear with $25 million and no intention to testify for the U.S. Attorney's office.
Gates lets Beckett know that she hurt an investigation her sister had going on early in her career by following the letter of the law. She ignored Elizabeth's argument of not taking action for the greater good. That was the beginning of the end of their close relationship. As for the case, video footage suggests Jamie Berman was paying Peter Cordero the $25 million to throw the case. This would have destroyed the U.S. Attorney's investigation. However, the question of why Peter Cordero was killed remains unanswered.
Jamie Berman plays dumb when questioned about the U.S. Attorney's investigation, but he does reveal that Peter wasn't wearing the wire when he was killed. He saw him drop it off at a mailbox store. That means someone at the U.S. Attorney's office is lying about what happened. Captain Gates works with her sister to determine that her colleague, Stephanie, is the culprit. She had drugs planted on Cordero to get him to play ball with her. She did it all to bust Berman. She claims she did it all for the greater good. Case closed. As for the relationship between Captain Gates and her sister, that seems to be back open.
Castle's guest list for the wedding has over 400 people on it. Folks like Michael Connelly, Jonathan Kellerman, Wes Craven and Stephen King are just a few of the friends he's inviting. Still, cuts need to be made. Castle suggests they ax Beckett's Aunt Theresa. After all, she put a nasty post about him on Facebook. Beckett reminds her betrothed that she later took it down. At the end of a long day, Castle and Beckett agree to take one minute only to invite all those who absolutely have to be there. They both stop writing after listing one person. The name both Castle and Beckett wrote was "you."