Based on Ernesto Alcocer's book and briefly about Father Marcial Maciel, a popular pederast in Mexico.

The movie was constantly compared to The Crime of Padre Amaro (2002) due to same topics and controversy caused between Catholic Mexicans during both premieres.

Many ideas and situations were based on director's real experiences on a seminary.

Juan Manuel Bernal did not pretend to perform the real Father Marcial Maciel, but he inspired on him to perform his character.

When Luis Urquiza called Juan Manuel Bernal to confirm the leading role, he was about to turn it down after reading the book where the movie is based because he felt afraid and because his religious manners. Then he read in the newspaper about a new case of a pederast in Mexico and he felt confident to take the role again.

Juan Manuel Bernal had medical issues during filming due to anxiety.

Juan Manuel Bernal was casted to perform a supporting role, but he asked the director to perform the leading role; Luis Urquiza accepted.

Luis Urquiza wanted to make a more powerful movie, but he was afraid to violate the young actors, so he wrote the screenplay being careful to not generate traumas on them.