Based on real events. Havana, November 1871. First-year medical students are imprisoned for an unjust accusation, but only eight of them will be victims of an unexpected outcome. After 16 years, in which Fermín Valdés Domínguez, friend and cellmate of the victims, has fought to prove the innocence of those young people, a new clue places him close to discovering the key that would unravel the hidden truth.