At the start of the game, player-character Jack is a passenger on a plane that goes down in the Atlantic Ocean in 1960, after ordered society in Rapture has collapsed. After surfacing, Jack finds himself the only survivor of the crash, and swims to a nearby lighthouse on an island, where he finds a bathysphere which he uses to sink into the ocean and enter the city of Rapture. An Irishman named Atlas uses the service radio found in the bathysphere to help Jack in making his way to safety. Meanwhile, Ryan, believing Jack to be an agent of a surface nation, uses Rapture's automated systems and his pheromone-controlled Splicers to try to kill Jack. Atlas tells Jack that the only way he can survive is to use the abilities granted by plasmids, and that he must kill the Little Sisters to extract their ADAM. Overhearing Atlas' words, Dr. Tenenbaum intercepts Jack, and urges him to save the Little Sisters instead, giving him a plasmid that will displace the embedded sea slugs in each Sister. Atlas says his wife and child have been hiding on a submarine and directs Jack towards it. Just as Jack and Atlas reach the bay where it is located, Ryan has it destroyed; an angry Atlas asks Jack to kill Ryan.