By Lee Gyu-lee

TvN's new crime thriller series, "Mouse," is enjoying a surge in viewership ratings, which soared to a new high on Thursday.

The latest episode scored a 6.2 percent viewership rating nationwide, with 7.2 percent in the Seoul metropolitan area.

The series started airing last Wednesday, with a 4.9 percent viewership rating. But ratings dropped to 4 percent when the second episode was broadcast, only to pick up again afterwards.

Directed by Choi Joon-bae, whose work includes the romance series, "Come and Hug Me," the thriller revolves around two police officers ― rookie cop Jung Ba-reum (Lee Seung-gi) and detective Go Mu-chi (Lee Hee-jun) ― hunting down a notorious psychopathic killer nicknamed the "predator." It was written by Choi Ran, who is known for penning other thrillers, including "Black" and "God's Gift: 14 Days."

Mu-chi has dedicated his life to catching criminals after witnessing the murder of his parents by a serial killer when he was young. About 26 years after the killer was put behind bars, another serial murder, the "predator," appears in town.

The story intensifies as it peels off the layers of connections between the murder of Mu-chi's parents and the "predator," as well as the relationship between the two cops.

The series' endless twists and turns and suspense become even more compelling thanks to the actors' performances, which seem to hit just the right notes to attract more viewers.

Thursday's episode ended with a huge cliff-hanger by raising suspicions that model cop Ba-reum may be a cold-blooded psychopath.

"Mouse" airs every Wednesday and Thursday at 10:30 p.m.