A man awakes disheveled; impulsively, he skips work, heading instead to the shore. On this chilly February day, a woman in orange, hair dyed blue, chats him up: she's Clementine, he's Joel, shy and sad; by day's end, he likes her. The next night she takes him to the frozen Charles River. After, as he drops her off, she asks to sleep at his place, and she runs up to get her toothbrush. Strange things occur: their meeting was not entirely chance, they have a history neither remembers. Our seeing how the lacunae came to be and their discovery of the memory loss take the rest of the film.