Kiss of the Highlander (The Highlander Series, Book 4) by Karen Marie Moning,http://www.amazon.com/dp/044023655X/ref=cm_sw_r_pi_dp_3Feusb12A444RVR4
Sometimes the silent souls who seek out Odd want justice. Occasionally their otherworldly tips help him prevent a crime. But this time it’s different. A stranger comes to Pico Mundo, accompanied by a horde of hyena-like shades who herald an imminent catastrophe. Aided by his soul mate, Stormy Llewellyn, and an unlikely community of allies that includes the King of Rock ’n’ Roll, Odd will race against time to thwart the gathering evil.