Life is just too cruel for the poor. 

"I need money to survive." 

With a bottomless pit of debt and his little sister threatened, Zack is dragged into the life of a currency mining slave. He sits in a cubicle and stares at a screen for forty hours at a time, slaving away for very little money, and eating nothing but instant noodles for days on end. 

But he gradually gets good at it. So good in fact, that his clear speed becomes unrivaled. If he kept this up, things could end up well for his family. 

Alas, life has other plans. Strange portals begin to appear across the world, bringing with them other-worldly monsters and game-like scenarios. It is up to Zack to refine his grind in a world where magic becomes reality, and performance in examinations could be the difference between riches and fame, and death.