Shamans, who heal with prayers and medicinal plants, are often a first stop for people seeking medical care in the highlands of Chiapas, Mexico. Indigenous Maya fear that doctors and nurses in the region's overcrowded government hospitals will not understand them or respect their customs. Many of them turn instead to Sergio Castro, a revered humanitarian and wound care specialist, known as "Don Sergio." 

In 1966, Castro began working in Chiapas as an agronomist and veterinarian. He witnessed alarming conditions in many villages and decided to help by building schools and water treatment systems. He also taught himself how to heal long-term wounds from burns or diabetes. Now 72, he treats over 100 cases weekly, free of charge.

Castro's work offers insight into the lethal consequences of cultural mistrust, the challenges faced by those who fall through the cracks in Mexico's dysfunctional healthcare system, and the difference one extraordinary individual can make.