Yuki Sanada has always felt like an outsider in his own skin. He struggles to fit in with his environment and goes from town to town with his grandmother, who is socially uncomfortable and insecure. Yuki aspires for a new beginning when he and his grandmother relocate into the picturesque beach town of Enoshima. The presence of fellow transfer student Haru, however, jeopardizes his reputation at school. Haru makes an initial impression, proclaiming himself to be an extraterrestrial and professing Yuki to be his buddy. He assigns the ludicrous duty of protecting the planet from a strange peril in the water to the hesitant Yuki and their classmate and fishing prodigy, Natsuki Usami. As these three get up to mischief and shenanigans,