The film opens with Freddie Quell being seen amongst his Navy crewmen as they go from their vessel to an island where they wrestle, drink and Freddie indulges to attempt to self-fulfill his lustful desires. He comes back from the war and gets a job working as a photographer in a department store, but he soon leaves after he assaults a customer. He then gets a job picking cabbages. Freddie has become proficient at making his own special version of booze, which he learned from working on his Naval vessel. He gives his homemade drink to the men, but one of them gets so sick he passes out and everyone accuses him of poisoning the man. Freddie denies it, but runs away from them.
He finds himself aboard a boat he wanders onto in the night. The vessel is captained by Lancaster Dodd, a man of self-proclaimed profession and the leader of the Cause, a group he's formed in order to heal people from past-life trauma. Dodd takes a liking to Freddie and his special brand of booze, and brings him into begin living and working with him and his family.
Freddie becomes connected to Dodd, as Dodd helps him to work through his painful memories. Soon after, Dodd is approached by a man who suspects his work to be a fraud. Freddie takes this personally and beats the man. Dodd is then arrested for misuse of funds, and Freddie fights off cops and is put in prison as well. The two bury their hardship and Dodd welcomes Freddie back.
Dodd later releases his second book about the Cause in Phoenix. His publisher criticizes the book and Freddie assaults him for it. Everyone in Dodd's family believes Freddie needs to be let go. Before this happens, Freddie leaves the Cause and seeks out Doris, a girl he knew before the war that he fell in love with. But, she's married another man and now lives in Alabama. Freddie then goes to the movies and falls asleep, but somehow Dodd tracks him down by phone and invites him to come to England to meet. Freddie does, but Dodd gives him an ultimatum: stay and give his life to the Cause, or leave and be eternal enemies of Dodd. Freddie doesn't answer, but we see that he has left by the end of the film. He picks up a woman and sleeps with her.
