"I'll pay back the 600 million won." Because of the debt that his father left behind, Seo Taeyoon finds himself dragged in front of Park Jaein, who's looked down upon for being an Omega. Taeyoon smells Jaein's pheromones and realizes that he's an Omega. Jaein declares that he will buy Taeyoon on the condition that if Taeyoon is bought, his debt will be considered repaid! Jaein now holds the leash that's connected to the collar on Taeyoon's neck. What happens when their dangerous relationship begins? And how does it end?