A young soldier testifies of his thoughts about the first world war, between disillusion, fear and hate, following his path through the letters he sends to his lover.

If Paris is the city of lovers, it is also that ... ex! Antoine does not dare to commit, Didier regrets his ex-wife, Father Laurent must celebrate the marriage of his ex, Julie, Serge is harassed by Lise, the ex of his girlfriend of the moment, while Greg consoles With the dog ... of his ex! So many characters whose lives will be telescoped in a joyful disorder and who could fall back in love! But of whom? Whether they obsessed us or loved to hate them, deep down, it is difficult to forget their ex!

Cast out of his insular community, a damaged and down on his luck man teeters between a life of crime and the path to redemption.