In July 1912, Booker DeWitt is taken by Robert and Rosalind Lutece to an island lighthouse off the coast of Maine. Told to "bring us the girl and wipe away the debt," Booker enters the lighthouse, which doubles as a rocket silo and transports him to Columbia.[32] Booker is soon pursued by the city authority when he is found bearing a scar of the letters "AD," matching the description of the foretold "False Shepherd" who will corrupt Elizabeth and overthrow Columbia.[33][34] Freeing Elizabeth from her tower, Booker narrowly evades her captor, Songbird. Reaching an airship, Booker promises to take Elizabeth to Paris; when she realizes they are going to New York City to wipe away Booker's debt, a tearful Elizabeth knocks him out. Booker awakens to find the airship under the control of Daisy Fitzroy, who offers to return the ship if Booker helps her arm the Vox Populi. Booker and Elizabeth join forces to secure weapons from a local gunsmith. However, several twists of fate result in Elizabeth having to overlay the contents of various Tears onto the present reality. Ultimately, they land in a world where Booker is a martyr of the Vox Populi whose "sacrifice" sparked open warfare between the two factions. Fitzroy, convinced that the non-dead Booker is "either an impostor, or a ghost," turns her forces against him. With Booker's help, Elizabeth kills Fitzroy to prevent her from executing a Founder boy. As they attempt to leave by airship, Songbird attacks the duo and they crash back to Columbia. Continuing onwards, they unravel a conspiracy behind the city's founding: Zachary Hale Comstock had the Lutece twins construct a "Siphon" device to inhibit Elizabeth's powers; Elizabeth is Comstock's adopted daughter, whom he plans to groom into taking over after his death; and Comstock plotted to kill his wife and the Luteces to hide the truth. After Elizabeth is captured by Songbird, Booker pursues her, but ends up in an abandoned facility with snow on the ground despite the month being July; it transpires that he is now in 1984, and has been brought there by the Elizabeth of that time. Because Booker did not stop Songbird, the elderly Elizabeth suffered decades of torture and brainwashing, becoming Comstock's tool and waging war on the world, with Columbia launching a massive attack on New York City. Old Elizabeth tells Booker how to control Songbird and returns him to 1912