The concept of self-sacrifice is central to this film, as the celebrated investigator "Moto" (played by Peter Lorre) finds himself incarcerated on Devil’s Island. His unusual goal is to befriend convict "Brissac" (Leon Ames), with the intention of aiding his escape back to London. There, Moto hopes to unmask the head of the “League of Assassins,” a group aiming to steal a valuable secret formula from industrialist "D…