Set in 1939, during the final year of the Spanish Civil War, the story unfolds at a remote orphanage called Santa Lucía, which shelters boys who have lost their parents in the war. A new boy named Carlos arrives at the orphanage and quickly realizes it's haunted by a ghostly apparition.

The ghost is revealed to be Santi, a boy who mysteriously died at the orphanage. Carlos begins to uncover dark secrets about the place, including betrayal, murder, and greed surrounding a hidden cache of gold intended to support the Republican cause.

As the supernatural presence intensifies, Carlos and the other boys must confront both the ghost and the living evils that surround them — particularly from Jacinto, a violent caretaker with sinister intentions.