In 1942 during World War II, Wing Commander Max Vatan, a Royal Canadian Air Force pilot serving on intelligence duties, travels to Casablanca in Morocco to assassinate a German ambassador. He is partnered with a French Resistance fighter named Marianne Beauséjour, who had escaped from France after her resistance group was compromised and killed. The two pose as a married couple and grow close, despite agreeing that in their line of work feelings can get people killed. Marianne, who is trusted by the Germans, secures Max an invitation to the party where they plan to conduct the assassination.