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....
Should we treat them as human 
or treat them as a robot?
فهل ينبغي أن نُعامله كبشريّ
أم نُعامله كروبوت؟
Sollte man ihn wie
einen Menschen behandeln
¿habría que tratarlo
como a un ser humano
¿habría que tratarlo
como a un ser humano
devrait-on le traiter
comme l’un des nôtres
vuol dire... 
che dobbiamo trattarlo da essere umano?
Nesse caso... Será que devemos tratá-lo
como um humano ou como um robô?
как мы должны к нему относиться:
как к человеку или как к роботу?
ก็ควรจะปฏิบัติแบบมนุษย์