Aoi Tendo is a young man whose throws are so strong that they pierce the wall. Aoi's goal is to catch up to Shingo Ouki, who set the all-time Koshien record by hitting twenty-four consecutive home runs off the field. Ouki's home rund sequences were against Yu Tendo, Aoi's brother, who died of cancer shortly after Koshien. Unfortunately, Aoi is a lot like his brother, making throws that are so strong that there is no catcher who can handle them, which equates to Aoi being a one-winged bird (as Ouki calls him). However, Aoi meets a boy named Ai who asked to be his catcher. Ai has never had the chance to do any kind of heavy exercise in his life, although he has read many books on baseball. But Aoi's pitches remind him of a story about a bluebird who brings happiness and is willing to risk his life to truly live and catch Aoi's strong pitches.