A scientist, Dr. Karell (Asther), has discovered a treatment that can indefinitely prolong his life, using glands stolen from human victims. Having kept his achievement secret for over a century of continuous youth, Karell now has to contend with the curiosity of his new girlfriend Eve (Walker), the increasing guilt of his colleague Dr. Van Bruecken (Schünzel), and a police investigation of his most recent murder. Above all, he needs a renewal of his treatment, or else the mortality he has been evading will catch him at last.