A commuter train crosses by the neighbourhood many times a day. A group of twelve-year-olds have devised a very dangerous game. The excitement consists in placing a coin between the tracks and as the train approaches, two of the boys — one jumping from each side of the track — must grab the coin before being ran over. He who recovers the coin is the winner. Pablo, the story's main character is a twelve-year-old boy nicknamed "Wooden Ball" because of his habit of continuously twirling a wooden marble with his fingers.
Pablo, the main character, lives with his family in one of the oldest buildings in the neighbourhood. His father, who owns an offal shop in the local market, is a despotic and aggressive man. He beats Pablo and forces him to help in the shop at all hours. Pablo's mother is a housewife with a weak personality. She lives in constant fear and feels incapable of confronting her husband. Pablo's grandmother, his father's mother, completes the family picture. The old lady can hardly move. She cannot care for herself and requires help even for the most basic tasks. Pablo's life is governed by violence, and by the embarrassment he feels among his peers over his father's behaviour.

A couple with several children has moved into one of the new buildings in the neighbourhood. One of the children, Alfredo, is enrolled in the same public school Pablo, attends. Pablo befriends Alfredo and gets to know his family.

Slowly, Pablo becomes familiar with his new friend's way of life: the apartment where he lives, the tattoo shop where Alfredo's father works and the circle of friends close to the family who share a similar background. The inherited philosophy of the 60's, the devastation caused by drugs in their generation and the lass, through disappointment, of the political ideals fought for during the transition period from dictatorship to democracy that occurred in Spain. This new world fascinates Pablo.

Alfredo's family begins to know Pablo as well. They become very fond of him, developing an emotional attachment. One day, by pure chance, they discover the violence the boy has to endure in his family life. After having been badly beaten by his father, Pablo takes refuge in his friend's house. Alfredo's father decides to shelter Pablo while he tries to come up with a solution to Pablo's predicament.

Happy with Alfredo's family, Pablo deludes himself with the hope that he will never have to return to the home that has caused him so much physical and emotional pain.

One day, Pablo receives a call from his father. The news that he must return home immediately is so unbearable, Pablo decides to run away. Alfredo and his parents search desperately around the neighbourhood.