In the world of Necat, strangers are warped into a white room an instant before they die. This room prepares them for a world not too dissimilar from their own, with one key difference: there is no one except this group of people and a demon. In this world, they fight for their lives to earn points and return to their natural world after the demon is defeated as if nothing ever happened. The cycle continues until they have accumulated enough points to break it.

NECAT follows the stories of many people who navigate their way through two worlds. Kyle and Matt are long-term friends who happened to die on the same day and find themselves both in Necat. Together, they discover the backgrounds of their fellow survivors, the truth behind the demons, and devise a plan to escape forever.