A Kiss of Shadows (Merry Gentry #1) by Laurell K. Hamilton

Enter a thrilling, sensual world as threatening as it is beautiful, replete with the consuming passions of immortal beings once worshipped as gods or demons. Full of earthly pleasures and dazzling magic, A Kiss of Shadows will hold you under its hypnotic spell.

Meredith Gentry, princess of the high court of Faerie, is posing as a human in Los Angeles, working as a P.I. specialising in supernatural crime. But now the wueen's assassin has been dispatched to fetch her back -- whether she likes it or not. Suddenly Meredith finds herself a pawn in her dreaded aunt's plans. The job that awaits her: enjoy the constant company of the most beautiful immortal men in the world. The reward: the crown -- and the opportunity to continue to live. The penalty for failure: death.