Su Tang, a frail young woman, is trapped in a terrifying game dungeon inside an ancient castle. Mysterious on-screen comments that only she can see keep warning her that she is nothing more than the pet of Pei Ye, an S-rank Boss, and that he will eventually devour her. Terrified, she cautiously tests his intentions at every turn, only to gradually discover that the seemingly cold-hearted Boss has been draining his own life energy to keep her, who is on the verge of death, alive. When outside players enter the dungeon, they treat her as a tool for clearing the game and try to manipulate and exploit her. As the dungeon approaches collapse, Pei Ye uses every last ounce of his strength to send her back to the real world, while he walks toward his own destruction. Three months later, on a rainy night, the doorbell rings. He has returned to her doorstep, this time as a living person.