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....
And with those guys, they'll dish out 
a fortune just because they're rare.
وهم مستعدّون دفع مبالغ طائلة
فقط لكونها نادرة
Die zahlen gutes Geld,
nur weil etwas selten ist.
Esa gente paga solo por algo inusual.
Esa gente paga solo por algo inusual.
Ils sont prêts à mettre le prix
pour un modèle rare.
e sono disposti a sborsare 
un mucchio di soldi per un pezzo raro.
e pagam fortunas por unidades
que são raras, só pela raridade.
и они готовы
щедро платить за диковинки.
พวกนั้นน่ะ แค่หายากก็ยอมจ่ายแพงแล้ว