Orphan Gavin·Lin avenges his benefactor Ryan—murdered by tycoon Owen·Xu—by assassinating Owen, but is shot and left for dead. At death’s door, a voice offers him a deal: surrender his soul to enter the "Demon Chapter"—a deadly supernatural world (tied to Diablo/World of Warcraft)—to earn "life time" and survive as a Thief, fighting demons and other soul-bound "Contractors". Back in reality, Gavin hides as high school teacher "Rhys·Lin" to protect Ryan’s 17-year-old daughter Laurel from Owen’s gangster brother. Torn between two worlds, he evades police, navigates classroom life, and endures the Demon Chapter’s cruelty—all to keep his promise… and cheat death.