Listen to our exclusive interview with author Mara Hvistendahl here. “No. No. No.” Mo Yun was flustered. The slim, 40-year-old Chinese citizen had just vacationed in California with her kids, where she had made good on a promise — a trip to Disneyland. Now they were at their departure gate at Los Angeles International Airport, preparing to return to Beijing, when agents approached and announced that they had a warrant for her arrest. They explained that she would need to be separated from her five-year-old daughter and 12-year-old son. The agents gave her two options: Put her children on a plane back to China alone to be met by a friend or relative, or keep them in Los Angeles, where they would be handed over to child protective services.  “You’re going to need to make a decision, OK?” a Customs and Border Protection agent told her. “Or we can make the decision. It’s up to you.” Mo Yun chose to put her children on the flight to Beijing, alone.