No GPS or weather reports—just a sailboat, the wild open ocean, and the constellations. Think you could find your way across the South ­Pacific?

In one of the cruelest marches in World War II, a battalion of American soldiers trekked through nearly impassable jungle in Papua New Guinea to battle the Japanese. Six decades later, James Campbell attempts to repeat the journey, and discovers a deadly trail, ravenous leeches, and a rare look into one of the last remote places on earth.