Before sunrise: An American man, Jesse, and a Paris woman, Celine, meet on a train bound for Vienna and decide to spend the day together before Jesse departs the next morning. Before sunset: Nine years following their first meeting, Jesse and Celine meet again, this time in Paris during Jesse's book tour, and spend the afternoon together. Before midnight: Nine years following their afternoon in Paris, Jesse and Celine are vacationing in Greece with their twin daughters and a group of friends. They look back on their relationship and grabble with the struggles of marriage.