Max Vatan (Brad Pitt) is an intelligence officer who meets with a Resistance fighter named Marianne Beausejour (Marion Cotillard) to take down a Nazi ambassador. After the mission, they fall in love, get married, and have a baby girl named Anna.
Max learns that Marianne is suspected of being a German spy. After doing some investigation, Marianne confirms to him that she really is a spy, but her feelings for Max were genuine. They try to make a getaway, but Max's commanding officer finds them. To avoid Max getting in trouble, Marianne commits suicide in front of them after telling Max she loves him and to take care of Anna.