Nineteen-year-old college student Sophia is knocked unconscious and kidnapped on her way to school. She wakes up imprisoned in the castle dungeon of the wealthy Hadson, with an iron chain collar fastened around her neck. Driven to paranoid revenge after his mother was murdered at a high-society ball years ago while all the guests stood by without helping, Hadson spots Sophia's name on the guest list and assumes she was one of those cold bystanders.
Forced to comply out of fear, Sophia transitions from fighting desperately to gradually figuring out the patterns of Hadson's temper, eventually developing a complex Stockholm syndrome toward him through their daily interactions. Hadson's murderous intent also wavers in the presence of this pure and fragile girl, and a forbidden affection blossoms within their captor-and-captive relationship.
Driven by jealousy, secretary Linda schemes to sell Sophia to a dark underground casino, but an enraged Hadson tracks them down and rescues her. During a birthday trip to an amusement park, Hadson unexpectedly learns that Sophia was never at the ball back then—she is completely innocent. Overwhelmed by immense guilt just as the glass of their Ferris wheel cabin shatters, Hadson risks his life to hold onto the falling Sophia, promising to set her free.
