BioShock Infinite follows Booker DeWitt, a former soldier and Pinkerton agent, who is sent to the flying city of Columbia to "bring us the girl and wipe away the debt." That girl is Elizabeth, a young woman with the mysterious ability to open "tears" — windows into alternate realities. What begins as a rescue mission spirals into a story of identity, regret, and infinite possibilities.

Columbia is ruled by Zachary Comstock, a religious zealot who envisions himself as a prophet. Over the course of the game, Booker discovers that Comstock and he are the same person — split by a decision made in a single moment. Years earlier, Booker, wracked with guilt over his role in the Wounded Knee massacre, was offered a chance at redemption by being baptized. In one timeline, he refused and remained Booker. In another, he accepted the baptism, was reborn as Comstock, and began building Columbia.
Comstock, infertile due to his exposure to dimension-hopping technology, travels across universes to find a child he can raise as his heir. He finds her in another version of reality: Anna DeWitt, Booker’s infant daughter. Booker, desperate to erase his gambling debts, agrees to give up Anna — but regrets it immediately. In a tragic moment, as he tries to reclaim her, the portal closes and her finger is severed — leaving her with the ability to exist between worlds.
Anna becomes Elizabeth. Her power to manipulate time and space is the result of being partially in two realities at once. As Booker and Elizabeth travel through Columbia and alternate dimensions, they begin to unravel the truth. The cycle of Bookers becoming Comstocks, stealing Anna, and the entire conflict, repeats endlessly — different lighthouses, different realities, same events.
In the game’s final moments, Elizabeth takes Booker to a point outside time, showing him the infinite lighthouses — each representing a different version of the same story. To break the cycle once and for all, Booker must prevent Comstock from ever existing. He allows Elizabeth — or rather, the many versions of her — to drown him at the moment of baptism, erasing the timeline where Comstock was ever born.
The story ends not with a clear-cut resolution, but a reset. In a post-credits scene, Booker awakens in his office to the sound of a child — possibly Anna — suggesting a timeline where he refused the baptism and kept his daughter. Whether this version remains intact is left to interpretation.
In essence, BioShock Infinite is about guilt, forgiveness, and the weight of a single choice. It challenges the player to ask: can you ever truly escape the consequences of your past — or must you face them, even across infinite realities?