A friend of Joe's is killed while trying to escape from kidnappers, but not before she slips a key into Joe's golf bag---a key her abductors will do anything to retrieve; Nick takes a part in a play in which Cassidy performs; Caitlin threatens to move the SIU off the barge and onto the shore.

Nash and Joe track their chief's murderer, who's involved in a billion-dollar money laundering scheme, and a turncoat federal agent to Las Vegas.  Cassidy proposes to Evan, and he accepts it, but while he's undercover, he was killed.  Nash breaks ther bad news to Cassidy, that Evan is dead.  Caitlin tells Nash her decision to leave the SIU and moves to Washington, D.C., where her sister just gave birth to a baby.