One day, Mai remembers that her perfect stepbrother is a character in a death game manga, and that one year later he will hold a death game involving all of his classmates, killing his sister in the process. Mai plans a variety of surprises for her stepbrother every day based on what he said in the manga, "Nothing unexpected happened, so I was bored," but as the days go by, he begins to show abnormal signs... Only I know what my brother's really like. Pepu's comicalization of Inada Sou's popular web novel!

Mystia Aren is the daughter of a noble family who just started at high school. She's surrounded by a group of adoring classmates and her charming fianc. Everything seems perfect.Except that this world is actually a dating sim called "Kyun Love", and she's destined to become the main character's evil rival! Mystia is determined to do everything she can to avoid her fate but it's not as easy as it sounds. Especially when all the boys keep falling in love with her!