I lie on my side at the edge of a muddy orange grove only 20 yards from the Rio Grande. Low-hanging tree branches hide me from the men on the riverbank, men I fear carry guns and drugs. I am within 10 feet of their white truck now. After a slow 50-yard zigzag on my belly, I wrap my body around the base of a tree to hide my heat stamp – just as my chaperones suggested. I peer through night-vision goggles toward the riverside commotion. Did they hear my knee pop as I adjusted in the soil?