Synopsis

Following a cataclysm known as the 'Apocalypse,' or 'Catastrophe,' a mysterious Tower calls to humanity, tasking those with power and qualifications to ascend it. During their climb, a 'Return Stone' appears, offering the ability to revert to the time of their summoning while retaining their memories. Numerous Tower Walkers choose to return to the past, but one person, referred to as an "incredible human", decides to continue climbing the Tower, despite having reached a significant floor and others having left.