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....
I'll apologize, too. I had 
the wrong idea about you.
سأعتذر أيضاً. أخذتُ فكرة خاطئة عنك
Auch ich muss mich entschuldigen.
Hab dich falsch eingeschätzt.
Yo también me disculpo.
Yo también me disculpo.
Je te demande pardon, moi aussi,
pour t’avoir mal jugé.
Anche io mi scuso.
Eu também te devo desculpas.
Tive a impressão errada de você.
Я тоже прошу прощения.
Зря на тебя наезжал.
ฉันเองก็ขอโทษด้วย