Out of the Darkness by Jaci Burton

Harlee has lived as a human her entire life, working as a psychiatrist on a secret government project evaluating captured werewolves and vampires. Then one night two strangers jerk her from her bed, blindfold her and turn her world upside down. She is taken deep into the realm of lycans and vampires and told an unbelievable story—that she is the daughter of a forbidden union between a vampire and a werewolf and now possibly the future leader of both their clans. She doesn’t believe them. Vampires and werewolves are the enemies of humans.

She hangs onto her humanity, her one and only goal to escape from her sexy and enigmatic captors before she loses her heart and possibly her very soul. Vampire Adrian and Lycan Duncan’s goals are entirely different—to mate with the fiery beauty and determine whether her dominant blood is vampire or werewolf. One merely desires her. One will claim her for all eternity. But dark forces turn what begins as a search for identity into a struggle for survival. Choosing love is the only thing that can save her.