Summer vacation! Seiji, Guri, Akane and Yuzu have invited Akua to go with them to the beach. Akane tries to get Akua to go swimming with her in attempt to get closer to Seiji's little sister, but Akua gives her the cold shoulder. Pouting at her brother and his harem Akua goes to swim by herself but a dark shadow looms beneath her. Meanwhile, summer also means tests of courage! Guri suddenly invites Seiji, Akane, and Yuzu to the school after dark for a test of courage but her real motives are to pair another young couple who have asked for her help. Seiji thinks something isn't quite right about the pair though...
Now we can always be together, Seiji-kun.
Jetzt können wir immer unsere
Zweisamkeit genießen, Seiji.
Por fin podremos estar siempre juntos.
Por fin podremos estar siempre juntos.
Nous voilà enfin seuls, Seiji.
Così potremo
 stare insieme per sempre, Seiji-kun.
Então vamos poder ficar 
só nós dois, Seiji-kun.
Зато теперь мы
всегда будем вместе, Сэйджи.