Episode 12 of Mouse begins in the past once more, as Jae-Hoon approaches a dog under a tunnel. There, he finds a dying woman kept under a blanket. Annoyed that his game is interrupted, he continues on.
We then jump back to the present as Ba-Reum makes himself a coffee and comments how his energy has been replenished. It seems not from the coffee though. A knock at the door suddenly jogs Ba-Reum’s memory where more details of the previous night come flooding back. Apparently he didn’t kill Hoon-Suk but instead stalked a cat and ended up striking it several times. The kitten however, is still alive.
On the news, a report breaks of a woman in her 70’s committing suicide. Ba-Reum immediately heads out, worried about Bong-Yi’s wellbeing. Following footprints in the mud, he uncovers a bloody and beaten Bong-Yi. It now seems likely that Duk-Soo was killed by Ba-Reum.
In the morning, Hoon-Suk’s Mother arrives to pick up her son. She certainly looks spooked and hurries off, telling him he shouldn’t have gone to Ba-Reum’s place. When they hurry off, Ba-Reum shows at the hospital to see Bong-Yi, who’s beaten and bruised. When Moo-Chi leaves, Ba-Reum stays with Bong-Yi until she awakens.
Meanwhile, Moo-Chi is brought into the station on the back of scrutiny from the news. They question where he was the previous night and it’s here Moo-Chi admits that he was mugged and beaten down. When he storms out, the rest of the investigation team try to work out who the psychopath could be.
Ba-Reum sneaks into the evidence room and places a knife in one of the boxes there. In the morning he acts like nothing’s wrong. In fact, he gets talking to Moo-Chi about the man who killed Duk-Soo. Moo-Chi is determined to catch “that sicko” and likens him to a psychopath. Given how suspicious Ba-Reum is acting, he doesn’t look happy at this.
In fact, with the President in the police station overlooking the whole case, Moo-Chi takes over and interjects. He runs through the details of the case – intentionally not using honorifics – and mentioning a “mistake” in the form of a cut in the wrong place.
Moo-Chi notices the burn marks and uses the Unabomber case as an example of how psychopaths cover up their mistakes to try and maintain an air of perfection. According to a police report it’s actually a cigarette burn. This gets Moo-Chi thinking, wondering whether the killer could be someone on their side.
Next up, Moo-Chi and Ba-Reum head over to interview Yu-Na. She managed to run away from Duk-Soo after throwing something in his face. She hid inside a locker but someone arrived and locked her inside. It wasn’t Duk-Soo though, and eventually the door was unlocked after an unspecified period of time. A glance toward Ba-Reum is enough to distract her, but Yu-Na eventually decides she has nothing to say.
Heading back to the hospital, Moo-Chi shares his theory with Ba-Reum. He believes Bong-Yi is the one responsible and it makes sense given she has a motive.
All evidence seems to point toward Bong-Yi now but Moo-Chi is determined to prove that theory wrong. He heads back to the crime scene he figures out what really happened based on what’s lying around.
Yu-Na heard a sound and when Duk-Soo turned she threw dirt on him. That sound brought out the killer, who watched Yu-Na struggle from afar. They moved the pipe and set a trap for Duk-Soo, using it to strangle the man with a chain. Given the strength needed to do this – and not to mention the cunning skill – it’s definitely not Bong-Yi.
However, Bong-Yi happened to find something that belonged to Moo-Chi at the crime scene. It seems like Ba-Reum actually dropped it though, judging by how he’s acting in the evidence room. Could he be trying to frame Moo-Chi?
Anyway, Moo-Chi himself continues to press for answers. This brings him to Yu-Na but she refuses to talk and remains tight-lipped. Instead this falls to Bong-Yi, whom the officers ask to help Yu-Na open up and admit the truth. This causes a big problem for Ba-Reum, who tries to do his best to make sure they don’t meet.
Part of this comes from Hong-Ju changing Bong-Yi’s clothes in the hospital parking lot. The CCTV footage confirms as much, as we cut back in time and see her wiping down the car. Unfortunately those clothes happen to be in trash bags, which Hong-Ju has inside her buggy. They’re covered in blood and the knife is there as well.
With everything pointing toward Ba-Reum, he shows up at Yu-Na’s place, where she confirms it was definitely him that locked her inside the locker.
In the morning, Shin Sang begins searching the surrounding area down by the shore. There, he finds the murder weapon wrapped in a rain coat. Bong-Yi is released from custody, prompting her to meet back up with Hong-Ju. Hong-Ju admits that she originally thought Bong-Yi did kill Duk-Soo but later realized it wasn’t her.
Moo-Chi takes Ba-Reum down to the docks and shows him what they’ve found. He admits he’s confused and unsure how to interpret this situation. As he glances at Ba-Reum’s wrist, the episode comes to a close.
Mouse returns this week with an intriguing episode and one that keeps the question marks firmly blinking throughout. Who is the killer? All evidence seems to point toward Ba-Reum but it seems everyone has a reason for killing in this show.
Hong-Ju is still a bit of a wildcard here while Bong-Yi was obviously after revenge that night. Ba-Reum is the most likely candidate but then Moo-Chi appears to have been there too, judging by the note found on the floor. Then again, this could also be Ba-Reum trying to frame him.
Ba-Reum still seems to be Jae-Hoon (the psychopathic boy from episode 1) but it seems like the show is throwing a curveball with this Yo-Han brain twist. It could well be that the empathy from Yo-Han is interfering with Ba-Reum’s psychopathic tendencies and making him question his own motives. Either way though there’s a lot going on here.
Mouse has been quite the intriguing thrill ride until this point but it’s definitely been a confusing one too! Hopefully this series starts to answer some of the more pressing questions because right now the show is answering questions… with more questions. It’s undeniably good TV though but we’re definitely going to need some answers soon.