After a catastrophic disaster ravages the world, the few surviving humans seek refuge in enigmatic towers that are now their sole chance for staying alive. The ones who rise to the higher levels are revered as "Astras." Baek Homin, a low-ranking underling, receives a circuit tattoo that enhances his abilities and changes his destiny. Equipped with the power to recall memories from his previous lives - all of which were as Astras - Homin sets out on a hazardous quest. Will the defense of the Astras be enough to shield him from daunting foes as he embarks on his new adventure?
