In this first-person shooter, you assume the role of an armed forces specialist dispatched to probe unusual occurrences in the ancient Egyptian city of Karnak. As you delve into the investigation, you discover that alien invaders, with a proclivity for mummifying humans alive, have seized control of the city. Your mission is to navigate through progressively challenging levels, contending with an extraordinary cast of adversaries, to complete the game.

PowerSlave is set in and around the ancient Egyptian city of Karnak in the late 20th century. The city has been seized by unknown forces, with a special crack team of hardened soldiers sent to the valley of Karnak, to uncover the source of this trouble. However, on the journey there, the player's helicopter is shot down and the player barely escapes. The player is sent in to the valley as the hero to save Karnak and the World. The player finds himself battling hordes of extraterrestrial insectoid beings known as the Kilmaat, as well as their various minions, which include mummies, Anubis soldiers, scorpions, and evil spirits. The player's course of action is directed by the spirit of King Ramses, whose mummy was exhumed from its tomb by the Kilmaat, who seek to resurrect him and use his powers to control the world.