“What have I done wrong?” That’s the question Hyo-in An asks herself as she’s ignored and bullied by her former friends at school. She used to get along with everyone, until Juhye Kim and the other kids she thought were her friends began excluding her from their group and treating her horribly. But Hyo-in has an ace up her sleeve that could turn this whole situation around. Her uncle, the developer of the messaging app KitTalk, has given her a special phone that lets her access the group chats where her ex-friends badmouth her behind her back. Her initial hopes of being included again turn into desire for revenge, and Hyo-in begins using the phone to her advantage, making morally questionable choices along the way.