Hugo Llor, a 12-year-old boy who spends most of his time on the streets. His day is also spent in the shipyards and his dream is to become a shipbuilding craftsman, although his fate is uncertain. Hugo's life is not easy, he is a very lonely boy and his mother is forced to move away from him, but he has the support and protection of a respected old man: Arnau Estanyol.
Bull and the TAC team must call upon all their collective experience to locate Bull's kidnapped daughter, and the abductor warns them not to go to the police. As Bull works to build the most important psych profile of his life, he begins to suspect the captor is someone connected to his past.