A monster manual with some information on opposing factions’s mooks and bigger baddies that PCs can run into working for the Tomorrow Legion. This book also includes a few simple missions that you can run in a pinch or use as a starting point for more complex sessions.

The Savage Worlds roleplaying system smashed together with the Rifts Megaverse setting (a post-post-apocalypse kicked off by the cataclysmic return of magic on Earth and the opening of inter-dimensional portals all over it) seems like a match made in multi-planar heaven.