Egyptian high priest Im-Ho-Tep (Boris Karloff) is condemned to be mummified alive along with the sacred scroll of Thoth, which he used in a failed attempt to resurrect his beloved Princess Anckesen-Amon. 3,700 years later, archaeologists unearth the Mummy. A foolish young researcher reads the scroll, bringing Im-Ho-Tep to life. The youngster goes mad as the Mummy grabs the scroll from him and shambles off into the night. Several years later brittle-looking Ardeth Bey (Im-Ho-Tep, now somewhat rehydrated) meets young Helen Grosvenor, the spitting image of his long-lost Anckesen-Amon. Smitten, Ardeth bewitches Helen, convincing her of her original identity. She feels for him but draws the line at his plan to kill, mummify and resurrect her again so they can spend eternity together. Panicked, Helen cries out to the statue of the goddess Isis – to whom Anckesen-Amon was a devoted virgin – and the idol saves Helen by zapping Ardeth into a pile of bones.