Joseph Gordon-Levitt and Zooey Deschanel star in this offbeat romantic comedy, the feature debut of music video director Marc Webb, which chronicles 500 days in the on/off relationship of Summer (Deschanel) and Tom (Gordon-Levitt). While Summer steadfastly refuses to believe in true love, asserting that real life will always get in the way in the end, Tom has thrown caution to the wind and fallen hook, line and sinker in love with her. Where can their so-called relationship lead?