Sydney learns that she is pregnant with Vaughn’s baby, and Vaughn is under investigation, suspected of being a double agent

Sydney teams with Renée to track down the murderer of a close friend, Jack enlists new agent Thomas Grace and Weiss is offered a promotion.

Sydney reluctantly partners with new agent Thomas Grace (Balthazar Getty) to track down Rachel Gibson (Rachel Nichols) -- who is suspected of working against the United States -- and Dixon accompanies Sloane from prison to acquire a possible cure for Nadia.

Sydney’s life is placed in danger when Gordon Dean discovers that Rachel is still alive, and Sloane waits for the outcome of his sentencing. Amy Acker (“Angel”) guest stars. Sydney’s life hangs in the balance when Gordon Dean discovers that Rachel -- aka Mockingbird -- is still alive. Meanwhile, Sloane awaits the outcome of his sentencing. Amy Acker (“Angel”) guest stars.

Sydney and Tom discover that the cryogenic-type container has been stolen by Renée, and Sloane must resort to desperate measures to get himself reinstated into APO.

Sydney guides a nervous Rachel on her first solo mission, and Sloane must make a decision that could betray his new-found trust with APO.

Sydney and APO try to find out for whom Gordon Dean is working and what his ultimate goal is. Sloane struggles for control over the group that claims to have a cure for Nadia.

Sydney and APO try to find out for whom Gordon Dean is working and what his ultimate goal is. Sloane struggles for control over the group that claims to have a cure for Nadia.

Sydney reunites with Vaughn. Sydney is reunited with Vaughn after being kidnapped and put in a hypnotic state in order to retrieve information from the depths of her mind. But unbeknownst to Sydney, her captor is a familiar face with a vested interest in Sydney’s future and the future of her unborn child.

The birth of Sydney’s baby, the return of Michael Vaughn, The resurfacing of Irena Derevko and a little help from former Agent Weiss are featured.

The birth of Sydney’s baby, the return of Michael Vaughn, The resurfacing of Irena Derevko and a little help from former Agent Weiss are featured.

Sydney returns to work early from maternity leave in order To save best friend will Tippin, and Sloane is close to Obtaining the cure for Nadia.

Sloane learns that the cure for Nadia could kill her, the search Continues for Anna Espinosa, and Sydney offers Renee a job at APO

Sydney must act quickly to gain the upper hand on Anna Espinosa When a mysterious chip is found implanted in Renée -- with ties to Vaughn -- And Sloane begins to have ghostly visions while working for Prophet Five.

Sydney stays undercover and partners with Sark to uncover Rambaldi’s final clue, Vaughn sees daughter Isabelle for the first time, and Rachel discovers Tom’s secret.

On the two-hour series finale, Sydney and Vaughn race to stop Sloane after he takes marshal and Rachel hostage, and Jack and Sydney have to keep Irena and Sloane from implementing their deadly plan.

On the two-hour series finale, Sydney and Vaughn race to stop Sloane after he takes marshal and Rachel hostage, and Jack and Sydney have to keep Irena and Sloane from implementing their deadly plan.