A trilogy of minimalist films written and directed by Richard Linklater and starring Ethan Hawke and Julie Delpy. Each film takes place over the span of a single afternoon or night, in a different European city.
The film starts on June 16, 1994 with Jesse meeting Céline on a train from Budapest and striking up a conversation with her. Jesse is going to Vienna to catch a flight back to the United States, whereas Céline is returning to university in Paris after visiting her grandmother. When they reach Vienna, Jesse convinces Céline to disembark with him, saying that 10 or 20 years down the road, she might not be happy with her marriage and might wonder how her life would have been different if she had picked another guy, and this is a chance to realize that he himself is not that different from the rest; in his words, he is "the same boring, unmotivated guy." Jesse has to catch a flight early in the morning and does not have enough money to rent a room for the night, so they decide to roam around in Vienna.
Nine years later, Jesse travels across Europe giving readings from a book he wrote about the night he spent in Vienna with Celine. After his reading in Paris, Celine finds him, and they spend part of the day together before Jesse has to again leave for a flight. They are both in relationships now, and Jesse has a son, but as their strong feelings for each other start to return, both confess a longing for more.
Nine years have passed since ''Before Sunset''. Jesse and Céline have become a couple and parents to twin girls. Jesse struggles to maintain his relationship with his teenage son, Hank, who lives in Chicago with Jesse's ex-wife. After Hank spends the summer with Jesse and Céline on the Greek Peloponnese peninsula, Jesse drops him off at the airport to fly home. Jesse is a successful novelist, while Céline is at a career crossroads, considering a job with the French government.