 In 1881, Michael Denning, an American soldier, and Hector Servadac, a French aristocrat, are about to have a duel over a woman that they both are infatuated with. However, just as the two men are about to shoot at each other, a comet strikes the Earth and the gravitational pull draws in the two men. Michael and Hector soon deduce that this comet has been periodically landing on Earth and gathering people and animals from various eras in time, including people and dinosaurs. The two men then decide to put their differences aside and fight for survival as well as help make peace between two warring tribes of cavemen.