We all have a secret buried under lock and key in the attic of our soul. This is mine . . .

In May 1980, 15-year-old Óscar Drai suddenly vanishes from his boarding school in the old quarter of Barcelona. For seven days and nights no one knows his whereabouts . . .

His story begins in the heart of old Barcelona, when he meets Marina and her father German Blau, a portrait painter. Marina takes Óscar to a cemetery and at 10 am, a coach pulled by horses appears. From it descends a woman dressed in black, her face shrouded, wearing gloves, holding a single rose. She walks over to a gravestone that bears no name, only the mysterious emblem of a black butterfly with open wings.

When Óscar and Marina decide to follow her they begin a journey that will take them to the heights of a forgotten, post-war Barcelona, a world of aristocrats and actresses, inventors and tycoons; and a dark secret that lies waiting in the mysterious labyrinth beneath the city streets.

From the bestselling author of THE SHADOW OF THE WIND comes a haunting gothic mystery - now an international BookTok sensation.