This enthralling version of the locked-room mystery takes place in Monteperdido, a village isolated by the surrounding Pyrenees. The villagers are distraught when eleven-year-old schoolmates Ana and Lucia disappear. Five years later, when Ana reappears under mysterious circumstances and the case is handed to Madrid investigative agents, old wounds are reopened, and everyone in town becomes a suspect in the cold case in this fast-paced thriller.