"One day, a tower appeared in the skies of all the major cities... Humans were suddenly summoned to become "Walkers", and they needed to clear the tower to save the world. . . Floor 77: The "Stone of Regression" was discovered. Walkers could now "return" to the past. Slowly... everyone left. . . Humanity's last hope, "Carpe Diem", was formed, joined by people who refused to abandon the world. . . The last Walker reached floor 100. He no longer knew what to believe." -- I do NOT own The World After the Fall, this is just a novel translation!