"This is the Scroll of Thoth. Herein are set down the magic words by which Isis raised Osiris from the dead. 'Oh! Amon-Ra--Oh! God of Gods--Death is but the doorway to new life--We live today--We shall live again--In many forms shall we return--Oh Mighty One.'"
A 1921 field expedition of the British Museum has discovered ancient artifacts and a mummy of Im-Ho-Tep: "It looks like he died in some sensationally unpleasant manner" -- "the contorted muscles indicate that he struggled in the bandages." The viscera were not removed, and we suspect that we're looking at punishment for sacrilege.
An inscription on a box reads, "Death, eternal punishment, for anyone who opens this casket. In the name of Amon-Ra, king of the gods."
Dr. Muller insightfully advises Sir Joseph Whemple to rebury the box, but impetuous Ralph Norton opens it, unrolls a scroll, and murmurs the text as he translates.
The mummy grows animate, grabs the scroll, and leaves. Norton screams and loses his mind, laughing insanely.
In 1932, Sir Joseph's son Frank is about to abandon another expedition. We hear about the consequences of the 1921 incident: Norton "died laughing, in a straitjacket."
The weird Egyptian, Ardath Bey, arrives promising them the "most sensational find since that of Tutankhamen. . . . I will show you where to dig" for the tomb of the Princess Ankh-es-en-amon.
The archaeological findings are brought to the Cairo Museum, where the question of Cairo keeping English findings arises (!) and Ardath Bey acts weird: "I dislike to be touched -- an eastern prejudice."
Dr. Muller's local party includes the half-Egyptian daughter of the English governor of the Sudan, Helen Grosvenor, who muses about "dreadful modern Cairo." As Ardath Bey reads from a scroll, Helen is long-distance entranced and leaves the party.
She rides to the Museum, bangs on the door, and faints into the arms of Frank Whemple. Later, on the Whemples' couch, she utters words in ancient Egyptian "not heard on this earth for 2000 years." When awake, she talks to Frank, asking about his archaeological violations, "How could you do that?" "Had to! Science, you know!" Frank confesses his attraction for the Princess when they opened her tomb. "Do you have to open graves to find girls to fall in love with?"
A museum guard discovers Bey with the scroll and is killed. The scroll is taken to the Whemples, and Bey comes seeking it, but is also taken with Helen.