A middle-aged American returns to Paris seeking redemption for the death of a man who tried to kill him in a fight 35 years earlier. Cut repeatedly, Matt Quinn knocks his attacker into the Seine, where the man drowns. Haunted by guilt -- he did nothing to save him -- Quinn encounters a charismatic young woman, a Muslim who considers herself a freedom fighter for her people. Leading a small band of female terrorists, one of whom she loves, she explodes bombs in a new reign of Terror. An eerie warning precedes each blast. She plans to set off one more, a big one, as Quinn and a tough French cop try to stop her, trekking through the Paris underground. Along the way, Quinn encounters love in the City of Lights and gets some answers about the man who tried to kill him.