S&T Conglomerate, Japan, Tokyo, Shibuya. The year is 2059.
The heart of Tokyo bustles with life as usual. Shibuya is never really still, with most shops open 24/7 and more than enough patrons to keep them that way.
In the heart of the city, a shadow looms. A rift between this world and another is torn open and its inhabitants pour into our world. These demons, bound to the machines that brought them to earth and by the humans they sign their contracts with, could destroy mankind or force it into permanent change.
In the restless Tokyo, dozens of machines come alive with a new mysterious app. Only the elite was to be allowed contracts with these dangerous beings, but technology changes hands fast and soon digital devil summoning will be somewhat of a commodity, turning the tides of the endless power struggle.