Laura García Rodríguez is adopted from an orphanage as a child. 30 years later, adult Laura (Belén Rueda) returns to the now closed orphanage, accompanied by her husband, Dr. Carlos Sánchez Rivera (Fernando Cayo), and their seven-year-old son, Simón (Roger Príncep). They plan to use the orphanage as a facility for disabled children. In the meantime, Simón talks about a boy named Tomás. He draws pictures of his new friend as a child wearing a sack mask. A social worker, Benigna Escobedo (Montserrat Carulla), visits Simón, as he has been adopted by Laura and Carlos. Simón is HIV positive. Angered by Benigna's unscheduled visit, Laura asks her to leave. She later finds Benigna in the orphanage's coal shed, but Benigna gets away. Simón becomes more enamoured with his imaginary friends but becomes angry when he learns from Tomás that Laura is not his birth mother, and he is terminally ill.