Soobin and Yeonjun are stepsisters who constantly fight and make fun of each other. One day, while Soobin was doing his homework, Yeonjun wore cat ears on his head and walked up to him and sat at the table. He handed out Soobin's homework papers. While Soobin sighed and looked at Yeonjun angrily, Yeonjun giggled and stuck his tongue out at Soobin. But Soobin couldn't help but stare at Yeonjun's cat-eared form and gulped as he silently watched her.