Yang Yohan is betrayed by a friend and falls into the Abyss, the worst dungeon imaginable. In this monster-filled hell, he encounters Lee Hyunmuk - one of Korea’s strongest awakened, who went missing in the Abyss years ago. But Hyunmuk, influenced by the Abyss, is half-mad. Together with him - who only occasionally regains his senses - Yohan struggles to survive, treating wounds and searching for food. But when the sudden onset of a flood hits, Hyunmuk completely loses his mind… In the brutal environment of the Abyss, with a festering leg wound, terrifying monsters that howl and attack - and on top of that, Hyunmuk’s madness... Yohan’s desperate struggle to escape this otherworld leaves him not a day without tears.