Undertow — Naomi Clark

Private Investigator Ethan Banning is a desperate man. He's desperate to rid himself of the demon possessing him. He's desperate to stop the nightmares and the evil urges that fill him. He's so desperate, he's agreed to quit smoking and drinking in exchange for help. Professor Benedict Walters thinks he can exorcise Ethan with clean living and ancient history, but he won't do it for free. Ethan's got to track down Heather, a missing colleague of Walters in the quaint and creepy seaside town of Beacon's Point. It should be simple...but Heather may not want to be found. Even if P.I. Ethan Banning can crack the case, he's still got to deal with a trainee necromancer, his own fading self-control, and an ancient entity that terrifies Ethan's own demonic denizen. So... yeah. Crack the case? Hell, Ethan Banning may not even survive it.