Sickly and asthmatic high school student Mikoto Hirose avoids social interaction at all costs due to a traumatic childhood. One day, during an asthma attack, he is saved by a popular junior, Kouta Yano. From that day forward, Mikoto can't seem to get rid of Kouta, no matter how hard he tries. Despite being polar opposites, with Kouta being a star baseball player with an infectious smile and Mikoto a sickly introvert who rarely smiles, the two gradually get closer...