After discovering a pair of skeletons that look like them at the end of The Penal Zone, Sam & Max also find a projector and four film reels nearby. The skeletons turn out to belong to their great-grandfathers Sameth and Maximus; they use the projector and reels, which somehow show their ancestors' last escapade.

In the not so distant future, the human race is imperiled by an omnipotent being bent on the destruction of our civilization. As Special Forces veteran "Serious" Sam Stone, you'll travel back in time to early Egypt to stop the dastardly Tah-Um, the very spirit of evil, before it can succeed in wiping out humanity's future.