The film tells the story of quick-witted teen Mark, contentedly living the same day in an endless loop whose world is turned upside-down when he meets mysterious Margaret also stuck in the time loop. Mark and Margaret form a magnetic partnership, setting out to find all the tiny things that make that one day perfect. What follows is a love story with a fantastical twist, as the two struggle to figure out how -- and whether -- to escape their never-ending day.