So much of Davey’s disappearance is impossible to understand, but we know this: After summiting the Sonora Pass, in Northern California, Davey stopped off Highway 49 to swim in the Mokelumne River. He left his duffel, his helmet, and his gloves on the Honda he was riding, and the key in the ignition. Then he went down to the water, leaving his riding gear, his backpack, phone, and laptop near the water’s edge. His most recent text message was sent from the river on the morning of Wednesday, June 5. Not long thereafter, his phone stopped communicating with the cell tower.