Mirror

A series of cat killings occurs in a neighborhood. The suspect is surprisingly Baek Si-Yun, the top student in his third-year middle school class. When Si-Yun finds himself in a situation where no one believes his claims of innocence, he sets out to find the real cat killer himself, accompanied by his friends Su-Min and Jeong-Hyeon, who believe in him. However, during their search for the killer, they become entangled with Hwa-Ja, an auntie working at an animal shelter, and Detective Jun-Woo, who lurks around Hwa-Ja, plunging them into an uncontrollable whirlwind of events...

(Source: KakaoPage, translated)