Romain, 23, is the watchman of a small Paris hotel. He does not know it yet but he is about to become a novelist... Madeleine is six decades older than him. She is his grandmother. Surprisingly enough, the age gap does not mean a thing for them: they mesh like magic. It looks as if they were born the same day. One day, Madeleine escapes from the nursing home where she has been placed against her will by her sons (one of whom, Michel, is Romain's father). Romain asks his employer for a leave and joins her in Etretat. Both have a wonderful day in the town of Madeleine's youth...