At midday on May 4, 1970, after three days of protests, several thousand students and the Ohio National Guard faced off at opposite ends of the grassy campus Commons at Kent State University. At noon, the Guard moved out. Twenty-four minutes later, Guardsmen launched a 13-second, 67-shot barrage that left four students dead and nine wounded, one paralyzed for life. The story doesn't end there, though. A horror of far greater proportions was narrowly...