Smash! is about two childhood friends (Shouta and Miwa) who share a common love for Badminton. Miwa, who's in love with Shouta, tries to persuade Shouta to apply to the same badminton school as her but the latter being of a carefree, easy-going and dense nature, brushes her away and states that he only plays badminton for fun.

However, Shouta's perspective of badminton quickly changes after a fateful encounter with Yuuhi (a mute girl). In his search for his badminton goddess Yuuhi, Shouta met Anan and thereafter, decides that he's going to pursue badminton more seriously...