On a misty, tropic Halloween Eve, an hour before midnight, I stopped paddling when coconut palms poked through the fog ceiling, blue fronds crystalline in the moonlight.

An island lay ahead. Maybe the right island. Hard to be certain, because the fog had thickened as it stratified, and my sense of direction has never been great.

If it was the wrong island, I was lost. If it was the right island, there was a chance I’d soon be detained, arrested, or shot, maybe killed.

I’m human. I was hoping it was the wrong island.

I checked the time as I reached into the pack at my feet and opened a pocket GPS. The navigational display was phosphorous green, like numerals on my watch. It was 11:17 p.m., I discovered, and I wasn’t lost. I’d arrived at my destination, Ligarto Island.

As I drifted, the tree canopy floated closer. Slow-motion fog cordoned off water and palms became brontosaurus silhouettes grazing in moonlight.

Fitting. Ligarto is Spanish for “lizard.”

I’ve spent years on Florida’s Gulf coast, exploring above and below the water. It’s what self-employed marine biologists do and I am a marine biologist. Usually. In all those years, I’d never had reason to set foot on Ligarto. Until tonight. I was here because a powerful man had demanded a favor. Doctors had told him he was in the final weeks of remission, with a month at most before leukemia immobilized him. Would I help him escape?