BioShock Infinite follows detective Booker DeWitt as he searches for Elizabeth, a young woman held captive in the floating city of Columbia. The city is divided between those who believe it should be open to everyone and those who want it to remain exclusive to Americans. Elizabeth has mysterious powers that create tears in space-time, exposing parallel universes. Booker and Elizabeth work together most of the game, with her able to contribute by tossing ammo or picking locks. They are pursued by Comstock, a spiritual leader, and his troops, including the giant mechanical Songbird.
The gameplay is similar to previous BioShock games, with vigors giving the player superpowers such as summoning crows or charming enemies. Booker can be upgraded with gear that provides permanent bonuses. The game features a variety of weapons, including pistols and rifles, as well as unique items like the Sky Hook. Vigors require salt to use, which can be collected by looting barrels or using infusions to extend the health bars. Players can also explore the world through the city's skyline, attaching to Skylines to quickly move around.