Upon waking up, Kang Chul-joon, a high schooler, found himself locked in a room with no explanation for how he got there. Fear took hold as he stumbled upon an antiquated MP3 player that delivered a terror-inducing message: he had been poisoned and had a mere three hours left to live. Drawing on his sharp intellect and passion for challenging conundrums, Kang Chul-joon took it upon himself to decode the clues and break free from the chamber. But one mistake resulted in a dire situation, with the poison spreading and him hurling up blood. Under Baek Ji-woon's new survival game, who was the genius behind "Struggle" and "Undead King," Kang Chul-joon must unearth the final hint to escape before it's too late.