Their son joined ISIS. Then they learned he had kids in a Syrian detention camp

In a small apartment outside Minneapolis, I'm watching two brown-haired brothers, ages 7 and 9, on a couch playing chess. They're speaking Arabic sprinkled with English. They stare intently at the board, their little brows furrowed.

After a stretch of silence, the older boy moves one of his pieces. "Check," he announces with confidence.