France, 1809. Captain Neuville is called to the front, leaving his future bride heartbroken. Her sister decides to write letters on his behalf to cheer her up.

Ariane and Hugo decide to exchange the lives they lead to escape from their routine, which after ten years of marriage, gives them the feeling of being hamsters in a wheel. She suddenly finds herself at the head of a construction equipment rental company and he tries to take the role of a house calling jewelry salesman...But is life really better when you live it on the other side of the bed?