On the tip of the Yucatan peninsula, the immortal Castillo family gathers in Tulum. Weary and haunted, they receive the names of fifty-two human sacrifices chosen once every fifty-two years for the Underworld, a tradition thought to have disappeared with the fall of the Aztec and Mayan empires.
Driving home one night, college freshman Zara Moss swerves to avoid hitting a ghastly figure in the road. Lucas Castillo witnesses the car crash, but when it comes time to supervise her abduction from the wreckage, he intervenes. Something is different about Zara: Lucas has been having dreams of her arrival for five hundred years.
As Lucas and Zara come together to put an end to the bloody sacrifices, they discover that the ancient tradition isn't so easily broken. The gods are angry, and they have until the Winter Solstice to drag Zara to the Underworld.