Repeat student Hyung-joon heads to a boarding school where he is immediately enamored of his beautiful math teacher.

Third time repeater Sang-goo needs special tutoring for his upcoming college entrance test. His father puts his son away in a pension together with a beautiful female teacher in hopes of motivating him.

Ji-eun decides to become a tutor for Sang-woo's son, Sang-woo, in order to make sure he has a rich boyfriend. When tutoring begins, Sang-woo, who was kicked by her older sister Hye-ran, is attracted to Ji-eun, who kindly teaches herself. One day, Sang-woo witnesses the love affair of his father and Ji-eun, and falls into a sense of loss. Meanwhile, Ji-eun overhears Ji-eun's conversations with a friend, and notices that Ji-eun's only goal is to meet her. In the end, Ji-eun notifies Ji-eun. Ji-eun arrives to attend the last class, and because of her appointment with Sang-woo, she eventually gives up her body.

Min-woo solves his sexual partner Yu-ri's financial troubles, and Sam-su-ha hires Yu-ri as Min-seok's tutor on the condition that he keeps his relationship a secret from Min-seok for the sake of his younger brother Min-seok's math grades. Min-seok gets excited when Yuri, who looks sexy his age, starts tutoring him, and he dreams of having sex that night. Meanwhile, Yuri doubts that Min-woo is dating another woman, but when she learns her door code while attending tutoring, she sneaks into Min-woo's room late at night to confirm. Yuri, delighted to see Min-woo sleeping in her room without having an affair, wakes up sleeping Min-woo and gives her a special service.