Yet another Boris Karloff vehicle, this film stars the actor as a kindly doctor whose noble experiments go awry, causing much death and despair. In this outing, the elderly Dr. Garth (Karloff) searches for a cure for mortality via plasma injections. Sentenced to death for a mercy killing,
Garth is allowed to continue his experiments in prison under the supervision of prison doctor Howard (Edward Van Sloan). Needing blood for the experiments, Howard gets it from the corpse of a prisoner who had just been hanged. Knowing he is to be executed the next day, Garth injects himself with
the serum, only to learn that his sentence has been commuted to life. The serum causes...