The Mummy

In 1127 A.D., a group of English crusader knights capture a large ruby from ancient Egypt and bury it within the tomb of one of their number. In present-day London, a Crossrail construction crew discover the knights' tomb and a mysterious man is authorized to investigate the uncovered findings inside the site. In a flashback, the hieroglyphics on a circular mural in the tomb, which date back to the New Kingdom era, tell the story of the ruthless Princess Ahmanet. She was first in line to succeed her father Pharaoh Menehptre only to be stripped of her birthright when his second wife gave birth to a son. Determined to claim the throne for herself, Ahmanet sold her soul to the Egyptian god Set, who gave her a special dagger to transfer his spirit into a corporeal form. After murdering her family, Ahmanet attempted to sacrifice her lover to give Set physical form, but her father's priests slew him and mummified Ahmanet, sentencing her to be buried alive for eternity inside a sarcophagus surrounded by mercury so that her monstrous form will not escape the tomb. Read more on Wikipedia.