Go Unha, who pursues sensation because his sense of pain is dull, rarely feels pleasure. For the first time, he experiences ecstasy in bed with Cha Gyuhwon, his current partner's younger brother.

However, the person is the worst combination for Unha: a younger man (연하), and surprisingly, a virgin who took a vow of purity (혼전순결).

Gyuhwon: "Then, are we having sex without getting married?" Unha: "No, you shouldn't act like I'm the only one who did wrong after sucking me off like that... Were you perhaps thinking of marrying me?" Gyuhwon: "Can we? Since we're both men?"

A younger man, a virgin, and a pre-marital purity advocate who harbors the fantasy of marriage after his first relationship-truly the worst. Unha thinks, "I messed up by sleeping with him."

Unha: "It's fine, what we did anally is invalid."

Regardless of Unha's thoughts, Cha Gyuhwon makes a solemn, life-altering promise to himself.