Other Than My Friend's Sister, Something Else

Seula has endured a long-standing crush, thinking that being friends would be enough. But when she learns Areum has accepted her boyfriends proposal, she breaks down. To soothe her torn heart, she gets drunk and calls her, confessing her feelings. The next day, she wakes up naked next to Areums sister, Daun! When Seula begins to piece the pieces of what happened together, she begs Daum to keep this a secret from Areum, to which Daum agrees under one condition Want to keep having a good time together?