Two incompetent and awkward stoners who live an easy life, having a best friend in an extroverted but lazy bum (Ed and Seth Rogen) who they have cracks in their relationship, specifically due to Ed/Seth’s bum-ness. While at a party with these best friends for different reasons (Ed and Shaun partying to get Shaun’s mind off his breakup and Seth and Jay going to James Franco’s housewarming party) the end of the world happens at random (a zombie apocalypse and the biblical apocalypse).

With a makeshift group of equally-as-incompetent people (Liz’ friends, Ed, and Shaun’s mom/James Franco, Craig Robinson, Jonah Hill, and Seth Rogen), including people who Shaun/Jay are uncomfortable with (Liz and her friends and Seth Rogen’s new friends) they fight to survive this apocalypse, with multiple mishaps and weird situations falling upon them. Eventually, Shaun and Jay have falling-outs with their best friend which, when paired with the peacekeeper of the group becoming part of the hordes against them (Shaun’s mom getting bit by a zombie and Jonah Hill getting possessed), leads to the climax of the apocalypse. With hordes of man-eaters after them (More zombies and Danny McBride’s cannibal group) they now fight for contrasting reasons (Shaun and his group fight to survive as long as they can, while Jay’s group fights to die in the best way they can).

When they’re about to lose in the face of being trapped with a giant threat (Shaun is stuck in the Winchester with zombies cornering him and Jay has to fight Satan) their best-friend ignores their falling-out and sacrifices themselves (Ed fights off the zombies and Seth sacrifices himself to Satan so Jay can make it to Heaven) but an unexpected event happens (The zombies are fought off by the army and Shaun and Liz are saved, Seth’s sacrifice takes him to heaven alongside Jay) and Shaun/Jay live happily ever after, with their dreams fulfilled and their friendship rebuilt (Shaun lives with Liz and still has a friendship with a zombified Ed, and Jay lives in Heaven with Seth)