In Paris, Lucas is a talented and successful computer scientist who is diagnosed with a rare and fatal brain disorder, which means he will rapidly lose his memory and his ability to speak coherently. Going from the hospital to a café, he is struck by a beautiful but eccentric young woman called Blanche. When she walks out on him just after he orders them dinner, he waits in the street until dawn. Driving by, she stops and weeps at his devotion, but has to go to work.