Henry Roth (Adam Sandler), a marine veterinarian living in Hawaii, meets Lucy Whitmore (Drew Barrymore) in a cafe and they develop a relationship. However, it soon emerges that Lucy suffers from anterograde amnesia due to a car accident she was in a year earlier with her father, rendering her incapable of forming new long-term memories. Her condition leaves her with no memory of anything between the day of the accident and the present as she cannot convert short-term memories into long-term memories as she sleeps. She believes every day to be October 13, 2002. Henry therefore must find new and imaginative ways of winning Lucy over every day, to the disapproval of her father and brother. Henry decides to remedy this using a diary and a tape reminding Lucy of events since the accident and explaining why she cannot remember these events; it eventually succeeds and the end of the film depicts Henry and Lucy as married.