Anime News Network: Yuichi Sakaki is the middle child and only brother of the Sakaki family. His older sister Mutsuko has a bad case of middle school syndrome (and has since before she was even in middle school), so she's spent most of Yuichi's life “training” him for the day when all of her chuunibyou dreams come true. He's always just brushed this off as his sister being weird, but on the day he begins high school, he suddenly develops the ability to read people's “statuses” over their heads. He can handle “big sister” or “classmate,” but what does it mean when he spots “serial killer” and “vampire” at school? Could Mutsuko have been onto something all along?