Fugitive is a short story in The Dresden Files series by Jim Butcher. It is set after "The Law", and it appears in the anthology Instinct: An Animal Rescuers Anthology.
Plot[]
Mouse is watching over Maggie Dresden as she settles in for the night; at midnight, Cerberus pays him a visit requesting his assistance to track down the Nemean Lion, which has escaped Hades with outside help. When Mouse objects that he's on guard duty over Maggie, Cerberus assigns it to a replacement, before accompanying Mouse to Castle Marcone, where they find the wreckage caused by the Lion, which, from a talk between Will Borden and Michael Carpenter, is riding Mister.