Nine years after meeting on an Austrian train, Jesse has written a bestselling novel based on their one unforgettable night together. As he finishes a promotional talk at Shakespeare and Company in Paris, Céline emerges, having tracked him down to discuss his book and the memories they shared in Vienna. With only a little time before Jesse must leave for the airport, they spend a day rekindling their romance, exploring Paris, and confronting the what-ifs of their past.