In 1954, US Marshal Teddy Daniels and his partner Chuck Aule arrive at Ashcliffe Hospital, a federal mental institution for the criminally insane on a small island in Massachusetts" Outer Harbor. They have come to find an escaped patient, Rachel Solando, who has left a series of encoded clues. The more they investigate, the more they believe that Rachel has summoned them there. As a storm approaches, Teddy and Chuck fear they may have stumbled into a nightmare world of CIA drug trials, eugenics and mind control. And the more they learn, the more they fear that someone is trying to drive them insane...