In a future world where invaders from another dimension have driven humanity to live on floating islands in the sea, Hida Kizuna becomes a member of the elite Amaterasu squadron.  In order to power up the mech suits of this all-girls combat team, he has to... do lewd things to them!?
Seriously, what is Sis planning?
Mann, was denkst du dir nur, Schwesterchen.
¿En qué estás pensando, Reiri?
¿En qué estás pensando, Reiri?
À quoi ma sœur 
peut-elle bien penser ?
Che cosa avrai in mente, sorellona?
Sinceramente, o que a 
Nee-chan tem na cabeça?