In 1982, a young boy wakes up one Saturday morning to a disheartening reality: not only is his box of favorite cereal empty, but his TV has no signal and he can't watch his beloved Saturday morning cartoons. However, hidden in the television static, an unusual and mysterious advertisement catches his attention. It's for a cereal named "Coo Coo Crunch," an unheard-of brand that promises an otherworldly experience.

Intrigued and hungry, the boy's curiosity peaks when, unexpectedly, a free box of this very cereal appears at his doorstep. The sender? Unknown. The boy, unable to resist, opens the box, unknowingly unlocking a portal to a nightmarish dimension.