Season synopsis
Contains spoilers for this season and earlier seasons.
Sydney learns Vaughn may have been a double agent named André Michaux. A rogue CIA officer shoots him, and the world is told he is dead; pregnant with his child, Sydney continues investigating with Renée Rienne. APO brings in Rachel Gibson, a hacker recruited from a covert criminal operation, while jailed Sloane seeks a way to revive his comatose daughter Nadia. The search for Prophet Five ties Vaughn’s past to Sydney’s new mission.
Sydney’s pregnancy limits her field work as APO pursues Prophet Five and the Horizon. She is abducted aboard a ship, escapes, and sends a distress message intercepted by a mole. Irina returns claiming to need help but is pursuing the Horizon for herself. In Vancouver, Sydney gives birth to Isabelle with Jack and Irina beside her. Vaughn survived the shooting and was hidden in Bhutan by Jack; he later reunites with Sydney. Sloane’s cooperation with Prophet Five deepens as he seeks Nadia’s cure.
Sloane’s cure revives Nadia, but she discovers his attachment to Page 47, the Rambaldi text tied to her illness. She throws it into a fire; Sloane rushes to save it and shoves her aside. Nadia falls through a glass table and dies from the shards. Sydney and APO turn against Sloane and Prophet Five. Sydney defeats Anna Espinosa’s impersonation and uses it to infiltrate the group. Sloane orders APO bombed; Thomas Grace sacrifices himself to delay the blast. Sloane pursues Rambaldi’s final artifact and nuclear missiles. At the tomb he shoots Jack and seems immortal in its red pool. Mortally wounded, Jack detonates explosives, trapping Sloane underground and dying in the blast. In Hong Kong, Sydney stops Irina, who falls to her death after choosing the Horizon over Sydney’s hand. Years later, Sydney and Vaughn live with Isabelle and son Jack.