Believer is a thrilling action-packed movie about a detective who goes undercover to infiltrate a powerful drug cartel in South Korea. As he gets deeper into the criminal organization, he must navigate a web of deception, danger, and deadly confrontations. With stunning visuals, intense action sequences, and a gripping storyline, Believer keeps viewers on the edge of their seats from start to finish.

Detective Won-ho risks everything to apprehend the leader of a vast drug cartel, known as 'Mr. Lee,' and becomes entangled in a complex relationship with two prominent figures, Brian and Rak. Meanwhile, a formidable and brutal figure named Big Knife emerges within their midst.