"One Day" is a film based on the David Nicholls best-seller about a boy and girl (Emma and Dexter) who meet on the night of their college graduation on July 15, 1988. She is a working-class girl of principle and ambition who dreams of making the world a better place and he is a wealthy charmer who dreams that the world will be his playground. For the next two decades – every July 15 – they meet.The story follows them by dropping in on July 15th of their lives every year for 23 years.