After learning that the man she has known as Michael Vaughn is under investigation and suspected of being a double agent, Sydney begins to question whether their business and personal relationship over the years had all been a lie.

Sydney is forced to partner on a mission with new APO agent Thomas Grace. They discover that Rachel Gibson -- a spy suspected of being involved in activities against the U.S. -- has something shockingly in common with Sydney.

Sydney and Tom discover that Renie has stolen the cryo container, and soon find themselves under siege by a group of mercanaries who want the contents of the container. Meanwhile, Sloane takes matters into his own hands to get himself back into APO.

Rachel receives a little help from Syd for her first solo mission while Sloan is back at APO in frequent contact with Gordon Dean.

Sydney and APO attempt to discover whom Gordon Dean is working for and what their end game is. Meanwhile, when the group claiming to have a cure for daughter Nadia continues to play mind games with him, Sloane struggles for control.