Andoheb travels to the Hill of the Seven Jackals in response to a summons from the The High Priest of Karnak, where a dying priest tells the ancient tale of Kharis. According to the legend, Kharis secretly loved Princess Ananka, but when she died the guardian stole sacred tana leaves to revive her. He was discovered before he could use them, and his punishment was to be buried alive, tongue removed, with the leaves buried alongside him. Priests later recovered him and kept him alive as the tomb’s relentless sentinel. Under the cycle of the full moon, the creature must be fed a brew made from three tana leaves to stay alive; if desecrators threaten the tomb, a ninth-leaf brew can bring him to life to defend the tomb, but anything beyond nine leaves would render him uncontrollable.
In Cairo, a down-on-his-luck archaeologist Steve Banning and his clumsy partner Babe Jenson stumble upon a fragment of a broken vase in a bustling bazaar. Banning is convinced it’s an authentic relic, and his reading of the hieroglyphs hints at clues to [Princess Ananka]’s tomb. He seeks the counsel of Dr. Petrie at the Cairo Museum, who supports the expedition, but [Andoheb] opposes them and even breaks the vase on purpose to mislead the pair. With Dr. Petrie’s backing, Banning secures funding for the trip, while Andoheb’s influence looms large. They also encounter the celebrated stage magician Solvani, who agrees to finance the quest in return for a share of the spoils. Solvani’s daughter, Marta Solvani, remains skeptical after a prior warning from Andoheb that the archaeologists might be frauds.
The expedition sets out for the Hill of the Seven Jackals, with Solvani along. Inside a tomb chamber they unearth the mummy of Kharis and the tana leaves, but there is no sign of [Princess Ananka]’s tomb. Andoheb confronts Dr. Petrie in the mummy’s cave and has the scientist feel the creature’s living pulse. After a nine-leaf tana brew is administered, the monster comes to life, escapes with Andoheb through a secret passage to the temple beyond the mountain, and begins to terrorize the camp. It strangles the Egyptian overseer Ali and eventually abducts Marta. Banning and Jenson split up to pursue the threat—Jenson circumnavigates the mountain, while Banning follows the secret passage they discovered inside the tomb.
Andoheb’s scheme deepens: he intends to inject himself and Marta with tana fluid to achieve immortality. Jenson arrives just in time and shoots Andoheb in self-defense, while Banning makes a bid to rescue Marta. The mummy appears, and bullets fail to stop it. Marta overhears Andoheb describe the immortality plan and warns that Kharis must not drink any more tana fluid. As the container of tana fluid is raised to the mummy’s lips, Jenson shoots it away. Dropping to the floor, Kharis fights to ingest the spilled liquid, and Banning seizes the opportunity to overturn a brazier, trapping the monster in flames.
In the finale, the expedition members return to the United States with the mummy of Ananka and the tomb’s diamonds, bringing a dangerous, powerful relic back home to what they hope will be a safer, more ordinary life.
