Within minutes of riding into Mexico in a rented white minivan last month, Latavia McGee knew that she was lost. She and three of her closest friends — close enough that she called them brothers — had driven from South Carolina to Matamoros in the state of Tamaulipas so that she could get a tummy tuck procedure. But this time, she was running late, had no phone service and had veered off course, Ms. McGee recalled in a recent interview. Also in the wayward van were Zindell Brown, Shaeed Woodard and Eric Williams, old companions with whom she had grown up in South Carolina. That morning in Mexico, they had been enjoying one another’s company, Ms. McGee said, as Mr. Brown, the best Spanish speaker of the four, asked strangers for directions.

---