After a catastrophe wipes out civilization, leaving only mysterious towers as humanity's last refuge, those who are able to reach the higher levels are revered as "Astras." Baek Homin is just a low-level lackey, but all that changes when he is tattooed with a skill-inducing circuit. Now, he has the power to recall the memories of his past incarnations... all three of whom happen to be Astras! As Homin sets out on a new adventure full of formidable foes, will the Astras be able to keep him safe?