"Hey, boyfriend, how you doing?" Souta Sakuhara is a first-year high school boy. His first ever girlfriend has just been stolen away from him by a "girlfriend." That girlfriend is Shizuno Mizushima, a tomboy who's also the tallest girl he's ever met, who's now his hated rival in love, taunting him with it. But then... "Since nobody else wants to be your girlfriend, how about you go out with me?" She suddenly pins him against the wall! She also started saying, "Give me a month, and I'll make you fall in love with me... I'm not going to let you go so easily!"