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....
This happened all the time at the Academy 
when I was studying rockets, too.
حدث هذا طوال الوقت في الأكاديميّة
عندما كنتُ أدرس عن الصّواريخ أيضاً
Während meiner Raketenstudien
auf der Akademie kam so was öfter vor.
Ya me pasaba cuando estudiaba
cohetes en la academia.
Ya me pasaba cuando estudiaba
cohetes en la academia.
C’était pareil à l’Académie,
pour fabriquer la fusée.
Mi capitava spesso anche
quando facevo ricerche sui razzi all'Accademia.