Bayron City, a pioneering metropolis built on a newly discovered energy source, promises every citizen a luxurious and comfortable lifestyle. In reality, young demon exterminator Shuu Ogata's life is far from extravagant. Despite running a private military business, he often struggles to make ends meet due to reckless expenses. Fortunately, Kisara, his demon partner, is more than eager to help Shuu with household matters—albeit a little too forcefully for his comfort.

The two work side by side, taking countermeasures against demon hazards, which stand as the biggest threats to the city. With danger lurking in the shadows, Shuu and Kisara strive to grant the town's safety; however, exterminating the possessed comes with a price unbeknownst to others.