From the product website:
WELCOME TO THE CITY OF THE FUTURE!
Millennium City is a high-tech, glittering metropolis built on the ruins of old Detroit — and the perfect city for superheroes and their arch-enemies! Full of adventure, intrigue, and supervillainous plots, it’s one of the most vibrant and exciting cities in the Champions Universe.
Millennium City includes:
a review of Millennium City’s history, geography, politics, and daily life
information about law enforcement, the underworld, and superhumans in Millennium City
details about locations of particular interest, such as Millennium City University, the Barlowe Hotel, and the Renaissance Center
character sheets for over a dozen new villains and NPC heroes, including Dr. Silverback, Jade Phoenix, Hazard, and more members of PSI
hundreds of scenario hooks for GMs and character ideas for players
a separate GM’s Vault section for “GM only” information, so players can use the book without learning any of the secrets the GM plans to create adventures around