As the two arrive in Paris the Joker takes Batman through the catacombs until they hear a faint roaring. They find themselves in "Le Cirque du Roi des clowns" (The circus of clown kings), a sect of upper-class citizens who worship the Joker and accommodate the duo.
The Batman discovers a man who appears to have died of extreme torture but Bat's detective skills allow him to see through the ruse and the ringing of bells directs the two toward the Notre Dame. On the cathedral the two meet the Trojan Horse who has Nina tied up; Batman directs the Joker to untie her as he distracts the villain but the virus slows him and he falls from the roof but is saved by the Joker.
Back on the roof the Trojan has left but Nina lays dead having been fed burning coal to emulate Portia, the wife of Brutus, indicating the duo should head to Rome for the final battle.