This rulebook details the gameplay of “Cthulhu: Death May Die," a cooperative board game where 1-5 players control investigators battling cultists and an Elder God. Players work together to disrupt a ritual, then defeat the Elder One across multiple stages. Gameplay involves dice rolls determining success or sanity loss, with various actions like attacking enemies, exploring, and managing stress and wounds. The game concludes with a victory if the Elder One is defeated or a loss if all investigators are eliminated or the Elder One overwhelms the world. Components include investigator boards, enemy figures, dice, cards, and tiles to create the game's map.