Natsuki sets his heart on creating a tidal power generator that utilizes the ebb and flow of the ocean's tides. He dives back into the ocean to find some materials and salvages some resin from the ruins of Ryuuji's family's factory. As soon as he gets back he gets to work. As they are working, Natsuki and Ryuuji exchange heated opinions over how the generator should be built. Atri intervenes and the two guys become closer friends. Meanwhile, a suspicious-looking character peeks at them from outside of the school....
But you said you didn't need me for that.
لكن قلتَ بأنّك لست بحاجتي
من هذه النّاحية
Du hast selbst gesagt,
dass ich das nicht brauche.
Dijiste que no hacía falta.
Dijiste que no hacía falta.
Tu as dit
que ce n’était pas la peine.
Sei stato tu a dire 
che non ti serve che lo faccia.
Você me disse que isso
não era necessário.
Но вы сказали, вам это не нужно.