Twisted

A runaway spell is the most dangerous weapon of all
The sea is the only life Juan's ever known-not counting the decade he spent as a Vampire. Those years gave him a healthy aversion for anything supernatural, but he's a shifter now. It's way better than being one of the undead, but he still doesn't trust magic. Paired up with Aura to teach him, he falls and falls hard, but she spurns his advances.
A history professor before the cataclysm, Aura deals in prophecies for her shifter pack. Juan is one hell of an attractive package, but he left a string of broken hearts during his years as chief navigator on cruise ships. She'd be an idiot to sign on for a fling. She has enough problems without adding a broken heart to them.
What began as an exploratory mission to see if anything is left of the world turns sour fast. A Vampire attack, a possessed priest, and a gateway to Hell mean fallout from the spell gone bad that pinned them in South America is far from gone. Retreat is tempting, but nowhere is safe. Surrounded by hardship, they sail on. Evil is leaching in from somewhere, and they have to find the breach.