Mun Yeonsu, a returning college student, gets blindingly drunk and accidentally stumbles into the wrong apartment - one that happens to share his same door code. Inside, he witnesses a shocking, intimate encounter between his department T.A., Yun Doah, and his classmate, Hong Yijae. Though he tries to process his mistake the next morning, Yeonsu find himself unable to forget the intense pleasure he caught a glimpse of. When he runs into the duo again, his chaotic and spicy campus life truly begins.