Karl Freund directed this story of an ancient Egyptian mummy, who comes back to life to seek the reincarnated princess he loved.
The preface quotes the Egyptian Thoth that death is the door to new life. A 1921 British archaeological expedition discovers a mummy, who was buried alive, and a casket with a curse on anyone who opens it. While an expert is arguing the archaeologist Joseph Whemple (Arthur Byron) should not open it, an assistant opens the casket and then goes insane laughing when he sees the mummy (Boris Karloff) come to life and walk away.
In 1932 Joseph's son Frank (David Manners) has returned and is told where to dig by Egyptian Ardath Bey (Karloff), finding a tomb sealed in 1730 BC. While Ardath Bey prays, Helen (Zita Johann) leaves a dance in a trance and comes to knock on the museum door, where she faints. Joseph and Frank Whemple take her to their house. Helen mumbles in ancient Egyptian. Ardath Bey is discovered in the museum by a man, who is later found dead of shock. Frank tells Helen about the tomb of the princess who looks like her. Frank kisses her and goes out. Ardath Bey comes in and meets Helen. Joseph hides the scroll, but Ardath Bey claims it is his and that Joseph must hand it over or die. Joseph is about to burn the scroll when he dies of a heart attack during Ardath Bey's incantations. The Nubian slave, mesmerized by Ardath Bey, retrieves the scroll and burns some papers. Dr. Muller (Edward Van Sloan) discovers the ashes are not the scroll and believes the Nubian is the murderer.
Helen visits Ardath Bey, who shows her their past - how he stole the scroll to bring her back to life and was sentenced by her father to be buried alive as a mummy. He says her spirit has wandered through many forms. Helen returns and tells Frank her dog is dead; she asks him for help. Helen is in bed under a doctor's care but wants to leave. Muller tells her to go next time so that they can follow. Under Ardath Bey's magic Frank collapses, and Helen is entranced. Ardath Bey and Helen in Egyptian dress see her mummy; he burns it, and she surrenders to him. Muller finds Frank and says Ardath Bey is going to kill Helen to make her a mummy. As they go and call to Helen, she prays to Isis. Ardath Bey is struck down by Isis and becomes a mummy again. Frank revives Helen as the scroll burns.
This story draws on mysteries of Egyptian culture that placed so much emphasis on death and rebirth. Helen's reincarnation is more believable than a mummy reviving; but this enables the audience to experience fear of supernatural powers and their eventual defeat by the heroic young archaeologist.