The indention in the sand is small, circular, rough-edged, unremarkable. The kind of thing you’d walk by without a glance in a place littered with shells, where dolphins jump the waves, and sandpipers hunt tiny clams along the shore. The top of this turtle nest is almost invisible, as it’s meant to be. I’ve come to Florida with two friends who are in a Mastermind with me. The place where we’re spending the week is home to over a thousand turtle...