"Best Seller" is a thriller centered around writer Hee-Soo (Eom Jeong-Hwa) who moves to a small house in a rural area after becoming involved in a plagiarism scandal. Hee-Soo then hears a mysterious figure tell horrifying stories and she writes a new novel based on those stories. Her novel becomes another best seller, but Hee-Soo's success is short lived. The stories in the novel are discovered to have been published 10 years ago. To prove her innocence, she goes back to the house to uncover the mystery that lies there.