After being extracted by APO, Sydney is reunited with her mother and together with her and Jack they travel to Vancouver in order to obtain a mysterious object called "The Horizon" which Prophet Five believed Sydney possessed. During this mission, which is complicated by the discovery that Irina works for Prophet Five and a subsequent attack by Peyton, Sydney goes into labor and — with the aid of Irina and Jack — gives birth to a baby girl, named Isabelle. Irina subsequently disappears with The Horizon.