In the 30's, a group of children that feel no pain are sent to an asylum to be locked in individual cells to avoid hurting other people and themselves. They stay there along the Spanish Civil War and Second World War. The prominent German Dr. Holzmann tries to rehabilitate the children and has conflicts with the Director Dr. Carcedo. Dr. Holzmann is fascinated by the boy Benigno, who is the smartest of the group and a survivor.
In the present days, David has a car accident where his wife Anaïs dies and their premature baby survives. He discovers that he has a severe cancer and he needs a bone marrow transplant to survive. He visits his parents and he learns that they are not his biological parents. David seeks out his biological parents and discovers dark secrets from his past.