Kane, codename Cairo, was an Egyptian who illegally immigrated to Italy only to end up working as a mercenary, after six years of hard work and enduring the guilt of each bullet he shot, he's finally retiring and going back to Egypt to see his sister again.

Right as he was about to take out his last target, a status window appears in his view saying something about a tower, after a moment Kane is teleported to a strange place to find his sister is also there.

In this new world, Kane and Jess make their way up the floors hoping to return to the real world.