With the music box in their possession and their secrets behind them, Neal and Peter turn to Mozzie to help make sense of a new mystery: a second song inside the music box, unlocked with Neal's key. Mozzie thinks it may be a code, but he won't know for sure without proper analysis.
Despite all their talk of disclosure, Neal and Peter are still keeping cards up their sleeves. While Peter and Diana continue their search for Fowler, Neal hatches a plan to con the FBI into helping him find Alex, who he thinks may have already cracked the code of the music box.
But Alex never cracked the code, and a mystery pursuer who is after the box is still hunting her. Neal tells Alex to steal the music box from Diana and donate it to the Russian Museum. Whoever is after her, he reasons, will let her go and set their sights on the museum.
When Peter learns that the music box has been stolen and that the Russian museum plans to do an invite-only public showing, he realizes Neal's plan all along: to draw out the person responsible for the plane explosion. And based on new evidence uncovered by Diana, it looks like that person is Fowler.
Furious that Neal has been using him, Peter takes Neal off the case. But with Fowler so close, Neal has no intention of staying benched. And no one, not even Peter or Mozzie, may realize how far Neal is willing to go to get his revenge...
