Crossing Hudson - The Guardians, #2

Beware of slayers in sheep's clothing. Maryann "Ryan" Mackenzie was raised to be the perfect mate to a powerful alpha male, with the sole purpose of helping him resist his dark side. What better way to fight darkness than to make her emulate all that is goodness and light? That was before everything she loved was taken away from her. Sweet Maryann is dead and Ryan has emerged from her ashes, a slayer with one final task to complete.
The last thing she needs is a hunky new Guardian getting in her way. Alpha male shifter Hudson Carver is many things, but a glorified babysitter isn't one of them. When he's summoned to take on a new charge, he's less than pleased. She may be a slayer, but there's a reason he's been assigned as her Guardian. She's got a whole heap of evil on her trail and he isn't about to let one hair on her head be harmed-especially when he realizes who she is to him.
His mate.