Smoke and shadows - Tanya Huff

Tony, a former street kid-turned-wannabe producer, is working on the set of a TV series about a vampire detective, where he discovers the dead body of a cast member.

Tony fears it has something to do with the strange shadows he has seen around the studio and when he turns to special-effects wizard Arra Pelindrake for help, she turns out to be the genuine article. The wizard escaped from a dangerous alternate dimension and has more than a passing acquaintance with the shadows. Together, Tony and his vampire friend Henry Fitzroy try to persuade Arra to cooperate but can't get her to face her fears and confront the shadows.

But they are soon left with nowhere to run as they are drawn into battle, for the shadows are intent on gaining a foothold in this world.