I can’t remember where we were — the middle of Nebraska? the middle of Missouri? — but it was time to visit another rest stop. We’d been driving for a day and a half, a day and a half and twelve hundred miles of sitting with virtually no exercise. My body was starting to petrify, my mood was increasingly surly. Marcy hopped out, opened the rear hatch of the M5, rooted around for a moment, then emerged with the antidote.