It is the last book in the Trilogy of the Mist. This fantasy novel takes place in a coastal town in Normandy, a few years before World War II. A family accepts a job at the mansion of a toymaker to pay off their debts. A mysterious lighthouse in the sea holds a distressing story about the death of a woman; the body of a teenager is found lifeless near the house, and shadows from the past lurk around every move the protagonists make. Everything leads to a series of events that awaken a dark memory seeking revenge.

Behind the entire story lies the darkness of men, intertwined with love, family, secrets, and an evil force that is not human. It is about the struggle between good and evil. Its characters are somewhat superficial and hollow. The style is mysterious, gothic, with scenes of horror, a lot of fantasy, long descriptions, intrigue, and tension. This work marks a turning point in the literary development of Spanish writer Carlos Ruiz Zafón (1964–2020).