A killer steals $100,000 in cash from an armored car and kills the guard. The special gel used to disable the security cameras was the same used in a heist that Esposito investigated nine years ago where he arrested his fiancee, Sonia Ruiz who is still in prison. In order to track down Sonia’s partner, she receives a furlough.
Sonia requests Javier to accompany her into the bar in Spanish Harlem to find her old partner. They don’t know that Ryan and Castle are listening in through a device in her ankle bracelet. They get a name and the two head to an apartment building but when a man holds a gun on Javi, Sonia makes a run for it. Ryan stops her but she says she only ran because the man pulled a gun.
Sonia has to go back to prison but Espo brings her to his mother’s home for one last family meal. He never told them she went to prison. He said he messed up and she left him. They have a wonderful night but Sonia makes a run for it out a window when she uses the bathroom.
Ryan promises to help Espo and not tell Beckett until they track down Sonia. Sonia’s old partner, Joey, has an alibi for the heist and murder. Turns out the victim was the inside man on the job and turned off parts of the security system. They find a burner phone in his garage that has phone calls to Sonia’s prison and Joey.
Espo doesn’t want to drag Ryan any deeper into his mess and ditches him. He tracks Sonia to her father’s place. He’s had a stroke. Turns out he was the mastermind behind the heist nine years ago and he has her gold. She’s trying to track it down because she doesn’t know where it is. Joey shows out and knocks Espo out. Ryan arrives at Sonia’s father’s place later and finds a blood stain on the carpet.
Joey and Sonia find the gold coins. Joey is about to shoot Espo when Sonia stops him, then Espo knocks him unconscious. Espo confesses that when he found out Sonia was a thief nine years ago, he emptied his bank account, grabbed his passport and considered going on the run with her but he couldn’t give up being a cop.
Beckett is called in. She, Ryan, and Castle arrive. Espo arrests Sonia. Esposito admits that he let his feelings get in the way and let his guard down with Sonia. Beckett says she understands but as his Captain she has to suspend him for one week without pay. He understands. Then Ryan takes a sick day so he and Javi can go out and get drunk together.
Back at the loft, Beckett has moved back in for good. Castle finds that Beckett has changed Lucy’s voice over to Linus and it just isn’t the same.