The film is based on "Carandiru Station", the original author Daruccio Varela is a cancer specialist. He has worked as a volunteer at Sao Paulo; Portuguese prison for 13 years and has an in-depth knowledge of prison life and prisoners. He recounted those touching stories to his patient, Barbank. Encouraged by Barbank, he took up the pen and wrote it down. Originally, I just wanted to see which newspaper was willing to publish it, but I didn't expect it to be published in the end, and it became a well-received and popular bestseller. Perhaps for the first time, the voices of those prisoners have been heard by the public.
Barbank, one of the book's first readers, found Varela's description "totally ruthless, clear, and unbiased in the slightest, like a doctor's diagnosis after reading an X-ray." In order to put it on the screen, he and two playwrights spent 3 years adapting it and revised 9 drafts. The biggest challenge they faced was sorting out the fragmented events of the original book into an organic narrative. In order to express the differences of human beings, they decided to use the method of sketching group portraits, by borrowing Robert Altman 's "Short Film Collection", to organize the film according to the characters. While they were careful not to lose Varela's neutral and objective attitude, Babank said: "This is not a film intended to attack the prison system. The whole point of the film is actions, not words."
