Marion Crane, a secretary from Phoenix, Arizona, steals $40,000 from her employer to run away with her boyfriend, Sam Loomis, who is struggling with debts and alimony payments. Desperate for a new life, Marion leaves town, planning to start afresh with Sam. As she drives across the country, her anxiety builds, compounded by a tense encounter with a police officer who becomes suspicious of her nervous demeanor. Continuing her journey, she trades in her car for a new one at a dealership, hoping to cover her tracks, but the pressure of her crime weighs heavily on her conscience.

During a stormy night, Marion stops at a remote motel off the main highway to rest. Bates Motel is run by a shy, seemingly well-mannered young man named Norman Bates, who lives in a large house on the hill behind the motel with his domineering mother. After checking in and conversing with Norman, who explains his strained relationship with his mother and his passion for taxidermy, Marion starts to reconsider her impulsive theft. She contemplates returning the money and facing the consequences of her actions, mulling over the decision during what should be a simple, yet unexpectedly significant, meal with Norman in the motel's parlor.