When Henry Jekyll’s experiments with cocaine have gotten out of control, he transforms into the hideous Jack Hyde. As Hyde he searches the London streets at night for his prey in whorehouses and opium dens. The police can’t catch him, he has nothing to lose but his mind

Now seriously mentally ill after working with Clouseau for such a long time, Inspector Dreyfus escapes from the mental asylum he was being held in and vows to destroy Clouseau forever. He kidnaps an eminent scientist and forces him to build a machine capable of destroying the world, with the intention of doing so unless Clouseau is delivered to him.