After the tragic death of his father during the tumultuous final days of the Spanish Civil War, young Carlos (Fernando Tielve) finds himself sent to a secluded orphanage in 1939. This institution, which doubles as a school, houses numerous other boys alongside key figures such as Carmen (Marisa Paredes), the weary headmistress with a prosthetic leg, and Dr. Casares (Federico Luppi), the compassionate assistant administrator. Among the residents is Jacinto (Eduardo Noriega), a hired hand whose character blends charm with menace, and Conchita (Irene Visedo), Jacinto's fiancée who works at the orphanage.
Carmen harbors concerns over the impending costs of caring for another child and reveals to Dr. Casares a hidden stash of gold bars, expressing her wish to be rid of them as they serve no purpose during such volatile times. Meanwhile, a bomb, which was dropped from a warplane, remains lodged in the courtyard, its presence a chilling reminder of the ongoing conflict.
Carlos quickly befriends two classmates, Galvez (Adrian Lamana) and Owl (Javier Gonzalez-Sanchez), sharing a bond over toys and comic books. However, during a dare on his first night, he encounters the sinister Jaime (Inigo Garces), who believes the bomb may still be active. When Carlos is lured into the kitchen by a chilling whisper stating that "Many of you will die,” he attempts to flee but is caught by Jacinto.
The next morning, the tension escalates when Dr. Casares demands that Carlos identify his accomplices from the previous night. Carlos's reluctance to betray Jaime leads him into further trouble. A confrontation between Carlos and Jaime culminates in Jaime falling into the cistern. Amid the ensuing chaos, Jacinto intimidates Carlos, reshaping their dynamics, but Jaime's respect for Carlos begins to grow.
Carlos later learns troubling truths from Dr. Casares. He discovers how the orphanage finances itself through selling spiced rum used for preserving fetuses, hinting at the dark undercurrents present among the staff. Casares's relationship with Carmen becomes a silent affair, overshadowed by her own troubled romance with Jacinto, whose violent nature casts an ominous shadow over the orphanage.
As whispers of a ghost named Santi (Andreas Munoz), a boy who vanished during the bombing, circulate among the children, Carlos decides to investigate. His dread escalates when he encounters a ghostly vision of Santi, heightening the fears steeped in the boys' conversations.
Under the specter of war, Dr. Casares pushes for the evacuation of the children. However, Jacinto's dark ambitions unfold as he seeks the hidden gold, leading to a confrontation with Carmen when she refuses to surrender the keys to the treasure. An explosive climax ensues when Jacinto sets the orphanage ablaze, resulting in an appalling death toll and leaving the remaining orphans to navigate through grief and dread.
In the aftermath, Casares and the surviving boys—including Carlos, Jaime, Galvez, and Owl—forge a fragile alliance as they stand against Jacinto’s inevitable return. Following Jaime's revelation of Santi's tragic fate and the explosive Christmas Eve, a collective resolve begins to take hold among the still-terrified children. As they devise a plan to confront Jacinto, their shared courage turns into a fierce will to survive.
As Jacinto arrives to claim his treasure, the boys rally together, fashioning makeshift weapons and staging a formidable rebellion. Despite their trials and the haunting presence of Santi, they ultimately succeed in overpowering Jacinto, leading to a resolution that sees him face the specters of his own deeds.
With the weight of the past finally lifting, Carlos and the remaining boys embark on a poignant journey away from the orphanage, watched over by the lingering ghosts of those who had fought alongside and cared for them.
