Marion Crane (Janet Leigh), a secretary in Phoenix, Arizona, always sneaks away at lunchtime to go meet her boyfriend, Sam Loomis (John Gavin). The two want to get married but can’t afford to because most of Sam’s money goes to alimony. After being trusted by her employer to take $40,000 in cash to the bank, Marion steals the money and runs away to California with Sam to start a new life.
Exhausted from driving the whole day, Marion turns off the highway and decides to spend the night at the Bates Motel. The motel is run by Norman Bates (Anthony Perkins), a young man dominated by his mother. After a long chat with Norman, Marion realizes that what she did was wrong, and she decides to go back to Phoenix in the morning to return the money. However, a week later, Marion has not yet returned home. Her sister and Sam look into the case of this mysterious disappearance.