Were you to glance up from the deserted beach below, you might mistake Tranquility Bay for a rather exclusive hotel. The statuesque white property stands all alone on a sandy curve of southern Jamaica, feathered by palm trees, gazing out across the Caribbean Sea. You would have to look closer to see the guards at the wall. Inside, 250 foreign children are locked up. Almost all are American, but though kept prisoner, they were not sent here by a court of law. Their parents paid to have them kidnapped and flown here against their will, to be incarcerated for up...