Kyung-Min, a man in his thirties, impulsively murders his wife after his business crumbles. Supressing his rage, he reunites with his old middle school classmate, Jong-Suk, who now works as a ghostwriter. Jong-Suk has aspirations to write his own novel but conceals his struggles from Kyung-Min. As they reminisce about their time in school, the two men recall their oppression by the wealthy and high-achieving "dogs," who belittled and bullied them for being poor, dubbed "pigs." However, their fortunes change when they meet Chul-Yi, the queen of the pigs. Kyung-Min takes Jong-Suk to their old school and reveals a shocking truth about what occurred 15 years prior.