Despite successfully escaping after having robbed the Federal Reserve, a notorious thief returns to retrieve the stash he left behind. Peter and Neal must put their differences aside to capture the criminal before he disappears for good.
The Roland brothers Josh and James, not on speaking terms for years, inherit a fortune from their eccentric, astronomy-obsessed father, but in the form of an intricate treasure hunt. Time presses as their only offspring is kidnapped by the infamous Brett Gelles. Pressed for time, Neal takes charge of the clues while the FBI tracks down the hostage. Meanwhile Mozzie plans to sell off a Degas from the Nazi treasure, but Neal learns about a partially preserved manifesto rendering that too dangerous.
The FBI spotted Detroit mobster Frank Deluca, who is looking for the legendary 'Detroit Dentist', an elusive con artist. Hearing that his Detroit orphanage mentor Mr. Jeffries is held hostage, Mozzie confesses that he's the Dentist, which even Neal never knew. Peter must put him in custody while Neal is to impersonate the Dentist, but Mozzie escapes on Jones's watch.
Peter and Neal are investigating a woman who's been married several to wealthy older men who died shortly after their weddings. They hope to get her by sending Neal into a bachelor auction hoping she'll get him. Peter goes with him and it's Peter whom she bids on. And when they learn that she has a partner, Peter has to keep seeing her which doesn't make Elizabeth happy.
Peter learns that Keller stole an Egyptian artifact and that he's trying to get into New York. Mozzie is anxious to unload the art but Neal wants him to wait. Peter asks Neal how Keller will get the artifact into New York, so he brings Peter to a fence he knows. Later the man turns up dead. When they learn of a person who handles artifacts Neal goes undercover.
Peter brings home a scanner that can pick up sounds from far away. He goes to work and leaves it, Elizabeth is there when she hears a conversation it's picking up that the neighbors are having. That's when she hears them talking about a crime they're planning. She calls Peter and tells him about it. He and Neal go to check it out but nothing is happening. He attributes the whole thing to her recent abduction. She then calls Mozzie and the two of them check out the neighbors. They discover something but instead of telling Peter, she calls Neal and asks for his help. ...
Peter takes the day in an attempt to give Elizabeth an extraordinary birthday complete with her parents. He leaves Diana in charge to find a missing Stradivarius with Sara and Neil all under the prying eyes of Agent Kramer.
When Agent Kramer returns to derail Neal's commutation, Neal races to right a wrong from his past. Peter in turn must choose a side. Set against the backdrop of Neal's commutation hearing, Neal will ultimately decide between fight and flight.