Human rights become profoundly personal when Ai Weiwei, China’s most famous artist, transforms Alcatraz Island prison into an astonishing expression of socially-engaged art focused on the plight of the unjustly incarcerated. At the core of the installation, called @Large, were portraits of prisoners of conscience coupled with the opportunity to write letters of solidarity to the imprisoned.

In her impassioned and powerful debut film, director Cheryl Haines captures this monumental exhibition from conception to fruition, and visits current and former prisoners—including American whistleblower Chelsea Manning—to learn how these letters were vital to their survival.