After waking from a nightmare, Nobuaki Kanazawa gets a mysterious text message in the middle of the night from someone called the King, regarding the so-called "King's Game." This message requires that his whole class take part, that the King's orders be carried out within 24 hours, and that no one is permitted to quit mid-game. Nobuaki and the rest of his classmates dismiss the message, assuming it is nothing more than an elaborate prank. However, it soon becomes apparent that failing to carry out the King's commands leads to bloody consequences, as those who defy the King die in horrific ways. With each command more extreme than the last, the body count begins to rise, and a cloud of turmoil and despair hangs over the class as they wonder if any of them can make it out alive.