AllMovie

A Navajo couple investigates XP, a genetic disorder that makes exposure to sunlight potentially fatal, and learns that it is far more prevalent on their reservation than in the population at-large: one in 30,000 vs. one in a million. They lost a son to the disorder, and now care for his sister, who also has it. Their study leads to a possible reason for the increased likelihood that Navajos will develop XP: the Long Walk of 1864, when their people were forced to relocate to eastern New Mexico.