Rookie police officer Jung Ba Reum (Lee Seung Gi) is as honest and steadfast as they come. Working alongside Officer Goo Moo Chi (Lee Hee Joon) at a local substation, the two partners are always willing to do whatever it takes to get the job done. Perfectly satisfied with his life, Be Reum’s world is rocked to its core when a string of brutal murders brings him face-to-face with a serial killer. Gripped by fear, the nation slowly sinks into chaos as the psychopathic killer continues his murderous spree. Always one step ahead of the officers chasing him, the only clue the killer leaves is the gruesome trail of chaos left in his wake. Determined to find the killer and bring him to justice, Ba Reum and Moo Chi set out to do just that, but even their best laid plans end in failure. In an attempt to understand what drives a person to such violent extremes, Be Reum and Moo Chi delve into the world of psychopathic behaviors. In their quest for the truth, some very poignant questions are raised. Questions which lead them to wonder, where does one draw the line between far and too far? Combining the highlights of the hit series, “Mouse”, “Mouse: The Movie” is a 2021 film directed by Choi Joon Bae and Kang Cheol Woo.