Heartless — Alison Gaylin

From the moment magazine editor Zoe Greene joins her lover Warren in San Esteban, an idyllic Mexican village, something is strange about the place and its people--from the black crosses that hang throughout the town to the blood-tipped spines of its strange indigenous plants to Warren's odd disappearances. Then, when tourists are found murdered, Zoe begins to ask questions. At even greater risk, she's finding the answers.