Marine biologist Henry Roth (Adam Sandler) finds the perfect woman, Lucy Whitmore (Drew Barrymore) and falls head over heels for her. When he sees her the following day, she hasn't a clue as to who he is. Lucy suffers from a rare brain disorder that wipes her memory clean every night. With the help of his friend Ula (Rob Schneider), Henry has to concoct a new and increasingly clever way to meet Lucy and get her to fall in love for him every day.