Marine Corps Master Sgt. Jerry Ensminger was a devoted marine for nearly 25 years. As a drill instructor, he lived and breathed the Marine Corps and was responsible for training thousands of new recruits. When Jerry's nine-year-old daughter Janey died of a rare type of leukemia, his world collapsed. As a grief-stricken father, he struggled for years to make sense of what happened. His search for answers led to the shocking discovery of one of the largest water contamination sites in US history. For thirty years, unbeknownst to the Marines living there, the Marine Corps improperly disposed of toxic cleaning solvents that contaminated the drinking water at North Carolina's Camp Lejeune Marine Corps Base. It is estimated that nearly one million Marines and their families may have been exposed to high levels of carcinogens through the water. 25 years after the wells were finally closed, only a fraction of former residents know about their exposure to the toxic chemicals. In the process of investigating the Camp Lejeune contamination, a larger issue comes into focus - the abysmal environmental record of the military. According to the Environmental Protection Agency, the Department of Defense is the United States' largest polluter, which raises grave questions about environmental conditions at other bases across the country. “Semper Fi: Always Faithful” is a timely and sobering story of the betrayal of US soldiers and is a call to action for more environmental oversight of military sites.