In an underground shelter-city encased in ice, Setsuna meets a young girl named Rinne and begins helping her with a mysterious invention. It can apparently help save the world, but its true nature is unclear. Meanwhile, the city itself will very soon perish.
and the underground strata have 
been left to fend for themselves.
والطبقة تحت الأرض تُرِكَت تتدبّر أمورها
بنفسها دون اعتماد على أحد
y los estratos inferiores
fueron abandonados a su suerte.
y los estratos inferiores
han sido abandonados a su suerte.
les niveaux souterrains
sont laissés à l’abandon.
e gli strati sotterranei
sono stati lasciati a cavarsela da soli.
e a camada subterrânea foi largada
para se sustentar sozinha.