EPISODE 1 – The Two
With no memory of her life during the past two years, Sydney struggles with a reality that is both foreign and frightening. To begin her journey back, she confronts Vaughn about his marriage and learns the shocking fates of Jack and Sloane. Meanwhile, Sydney is granted temporary CIA clearance on a case that may help her regain her memory.

EPISODE 2 – Succession
Sydney, on the hunt for the truth behind her missing two years, confronts Sark, who is behind bars in CIA custody. But when a new terrorist organization, The Covenant, demands Sark in exchange for two scientists they've kidnapped, Sydney has to arrange a prisoner exchange against her will. Meanwhile, Jack confronts Sloane about Sloane's possible role in his daughter's disappearance – uncovering a surprising secret in the process. And Sydney meets Lauren Reed, Vaughn's wife.

EPISODE 3 – Reunion
For the first time in two years, Sydney and Vaughn are reunited as a team to prevent Sark from destroying the nation's satellite communications system. Jack must find a way to stop Marshall from uncovering the identity of a murderer, and a suspicious Sydney accompanies Vaughn and Lauren as they meet with Sloane to ask for a favor.

EPISODE 4 – A Missing Link
While trying to infiltrate a group bent on retrieving deadly biological weapons, Sydney discovers a link to her missing two years in the form of Simon Walker, the dangerous leader of the team. Vaughn struggles with his own feelings of jealousy and longing while Sydney is on her mission, aware of the pressure his job is putting on his marriage to Lauren.