It’s high summer in 1942, and a group of young men wait in line at a U.S. Navy enlistment office in Houston, Texas. Some of the men are so young they’d be better described as boys. It’s easy to imagine that these would-be recruits are daunted by the momentous step they’re about to take. But one of them, Calvin Graham, is especially jumpy. And it’s no wonder, because he’s just 12 years old.