Shirogane Takeru found himself inexplicably transported to a world that resembled his own in many ways, with one major difference: For nearly 30 years, mankind has been at war with the alien BETA, who have succeeded at wiping out over half of humanity and had nearly captured the entire Eurasian continent. As Takeru tried to come to grips with this bizarre new reality, he realized too late that the majority of humanity will be abandoned with the Earth, as the chosen few escape to the stars, hoping to find sanctuary.

Now, equally inexplicable reasons, he finds himself returned to the first day of his time in this alternate world. Will the experiences and knowledge he has gained allow him to make a difference?
while everyone else is stuck 
on Earth, waiting to die?
بينما يعلق البقية على الأرض وهم في انتظار الموت؟
während alle anderen auf der Erde
festsitzen und auf den Tod warten?
mientras que el resto espere
la muerte en la Tierra?
mientras que el resto espere
la muerte en la Tierra?
tandis que le reste
est condamné à mourir sur Terre ?
mentre tutti gli altri resteranno 
bloccati sulla Terra a morire.
enquanto o resto da humanidade fica
na Terra esperando para morrer?
и оставить остальных на Земле
 дожидаться смерти?