The bring the music box to Mozzie who helps the decipher the second code inside the music box. Neal puts it together that Alex must have been able to put together the music box had a secret code - so off they go in search of her.
The easiest way to catch Alex is to con the FBI by putting together a fake case that Neal knows Peter will want to follow.
Neal gets Alex to break into Diana’s house to steal the music box and donate it to the museum in order to drawl Fowler out of hiding.
Meanwhile, Peter is hot on the case to find Fowler. Peter finds out that Fowler was the one who placed an order for the parts of the bomb.
Neal breaks out of his ankle monitor and heads to the museum where Fowler has barricaded himself inside. With action packed moves, Neal breaks in to Fowler’s room and demands to know why he killed Kate.
Fowler tells Neal that he didn’t kill her, but Neal doesn’t believe him. Peter rushes in and is able to disarm Neal.
Fowler tells them that it was a bigger man that he didn’t know who it was. Kate told Fowler that she really wanted to get away with Neal and was the one who came up with the idea to blow up the plane. Fowler had no idea why the plane exploded early.
Later, Peter shows Fowler a picture of the unnamed man and Fowler tells him he knows who it is - a man he trained with back in the day.
Peter gets a call of a homicide in the same store Neal was at. Diana and Peter get there and the music from the music box is playing. There’s also video surveillance of Neal in the store. Peter knows that the killer will be after Neal.
Diana and Peter rush in to catch the killer and Alex turns up at Neal’s place. She tells them that she was just saying good-bye to Neal and leaves. Peter tells Neal why they ran into his place when Neal puts together it wasn’t him that the killer is after, but Mozzie.
The episode ends with Mozzie sitting on a park bench and the killer coming out of nowhere and shooting him in the chest.