Takuma, Hinata, Yui, Hamaji, and Maki go to the beach together to have fun, but before long Hamaji's younger sister Yukiji shows up and tries to take Hamaji back home. In the end, Takuma and the others agree to let her stay, though for a while Yukiji attempts to hurt (even kill) Takuma or otherwise separate him from the others due to her love for Hamaji. When Yukiji is confronted by the others about Takuma, she runs away and swims in the sea, but when her leg cramps, it is Takuma who attempts to save her, though he nearly drowns himself...