From the back cover:
Demons Rule is a Champions adventure featuring the Demons, a group of extra-dimensional horrors masquerading as street kids. It includes an intricate mystery, 10 fully detailed short encounters, complete write-ups for all six Demons, and maps for the major encounter locations. There are also details for the other street gangs in the city.
The Demons rule the streets, and their turf is expanding. Can you stop them before they take over everything?