Juan Miranda is a cigar-chomping, salt-of-the-earth peasant with a Robin Hood heart. John Mallory is a dynamite-tossing Irish revolutionary who has fled to Mexico to practice his skills. Together, they're a devilishly volatile mix of anti-establishment philosophies and violent tendencies as they attempt to liberate political prisoners, defend their compatriots against a well-equipped militia, and risk their lives on a train filled with explosives.