During his day job as a Spanish criminal interpreter in a small town in California, filmmaker Rodrigo Reyes (499) met a young man named Sansón, an undocumented Mexican immigrant who was sentenced to life in prison without parole. With no permission to interview him, Sansón and Reyes worked together over a decade, using hundreds of letters as inspiration to create a portrait of a friendship navigating immigration and the depths of the criminal justice system.