Seventh Circle (Vampires Realm Romance Series #4) by Felicity Heaton
Approx. 106,760 words.
Published on December 27, 2009.
Lincoln is a powerful pureblood vampire with a problem. He's caught up in a prophecy and has little time left to unravel the mystery of the contract between his lord and the Devil before he dies. When witches foretell that a vampire hunter will save his life, he's prepared to work with his most hated enemy, but he isn't prepared for the forbidden desire he feels when he meets her.