Parallel universes exist.

Ten years ago, a terrorist organization called Liroli waged an all-out war against the World Order, bent on obtaining the means to travel between these parallel universes. Although the war ended with the government's victory, it was not without consequences. A poisonous element known as Lorine began leaking from the other worlds, bringing a plague that wiped out a third of humanity — the infamous May Death. Those infected gained strange abilities, in exchange for their certain death in a year.

To counter the great plague that threatened humanity's survival, the government launched the World Restoration Project: gathering those infected and sending them into Lorine-polluted parallel worlds to seal the leaks between them. But it isn't that easy a task, as many dangers lurk behind these worlds, while those infected must deal with their own looming deaths.

This is the story of Jack Waterfelt, the only human in the world immune to the May Death, and the 43rd Sealing Squad.