Power corrupts. Can Thomas resist the lure? Thomas may be the first magical cougar to go freelance, but he still has a lot to learn about selecting clients. Guilty over the injuries suffered by his friend and client O'Meara, Thomas resolves to collect enough magical essence to get her healed. Teaming up with an under-appreciated cabal of technomagi, Thomas finds himself battling encroaching mages, vicious spirits, and the forces of the multiverse itself to gather the energy mysteriously popping up all over Grantsville. Will the promise of absolute power corrupt the people and town he cares for, or will Thomas overcome his own obsession in time to save the people most in danger? Marking Territory continues Thomas' adventures in the second installment of Freelance Familiars. If you like the Dresden Files, you'll love this darkly humorous urban fantasy with an animal twist.