Volume 1: Up-and-coming pitcher Saiga Kanata is a battery together with his childhood friend Shinonome Haruse, who is also the baseball team captain and catcher. When they were kids, Haruse, who just moved into the neighborhood, started talking to the introverted Kanata. Ever since then, they grew up together like brothers: Haruse as the "older brother", and Kanata as the "younger brother". However, Kanata pines and lusts for his "older brother". Kanata broods, wondering how long their pretend-play at brothers will continue...Note: *"Nanahoshi" comes from the Japanese word for the seven-spotted ladybird, "Nanahoshi Tentou(mushi)".*A "battery" in baseball refers to the duo of the pitcher and catcher.
