On a deserted island, Hank (Paul Dano), who is not good at communicating with others, has long despaired of life, so he decides to end his life with his own hands. At the critical moment, a corpse floats to the beach. The corpse (Daniel Radcliffe) is smelly and farting, and although it is pale and swollen, it seems to be alive. Hank is overjoyed and names this unusual friend Manny. What makes him even more excited is that Manny is like a multifunctional Swiss Army knife, helping him solve many practical problems such as making fire, chopping trees, and drinking water. The appearance of Manny opens the door to a new world for Hank, and the god of death seems to have escaped. The loser Hank embraces his fantasy world. Hank and Manny, this pair of weird friends set out on an unusual journey...