We were at our secret beach, my wife and I, enjoying a stretch of sand that remains remarkably unfettered from what passes for progress. There are houses along it, but they are built with a certain sense of scale that does not detract from what was there long before them. Beaches like that are rare around here. And after you've found one, you become protective of it.

My wife had taken up residence in her beach chair, absorbed in the latest Sue Grafton. I was piddling around in the water, maybe 50 yards offshore, where I'd come across a patch of sand dollars on the sea bottom. I don't know anything about the life cycle of sand dollars except that come every spring they seem to congregate en masse in certain stretches along the Gulf where they do whatever it is sand dollars do to ensure the perpetuity of their kind. It is quite a wonder to come across them, to pluck up a few specimens with your toes-big ones, tiny ones, in-between ones-to briefly admire them and then let them settle softly back down to the sea bottom to resume their sand-dollar business. So I was wholly enjoying that moment-the slaphappy leaps of mullet, the dive-bombing pelicans, the richness and day-to-day surprise that is the Gulf of Mexico. So far removed from the anxiety and turmoil of the world ... that is why we go to the beach.

And then the guy with the spear gun showed up. He was in his 20s, I'd guess, tan and fit and strutting with his weapon in hand. He plunged in near a cluster of rocks and pilings and when he surfaced moments later a tiny fish was impaled upon his gleaming spear. It was a really tiny fish-a sailor's-choice it looked like-smaller even than the palm of my hand. He yanked the fish off the spear and tossed it away. That's when I lost it.

"What the hell are you doing?" I yelled. The guy glanced my way, then dived for more prey. When he resurfaced I was on him, repeating my question in somewhat coarser terms.

"Hey, it's a new gun," the guy said. "I was just practicing."

I'll spare you the exact details of what came out of my mouth after that, but it ended with me suggesting that he could take his spear gun and, well, practice somewhere else.

"Is this your beach?" the guy asked.

"Yeah, matter of fact, it is," I said.

It wasn't until that instant of standoff that I became aware that the spear gun was only inches from my belly. By this time my wife was standing up by her chair. Several other beach goers had gathered to watch the confrontation. But it was over just like that. The guy shrugged and walked away. I flatter myself to think his tail was tucked between his legs.

"Did it occur to you that you were almost in a fight with a man carrying a loaded weapon?" my wife said.

"Man's gotta do what a man's gotta do," I said, and if I'd had a hat I would have tipped it.

"My hero," my wife said, and went back to her book.

I waded out to rejoin the sand dollars. If it is possible to swagger in waist-deep water, then that's what I did.

Eternal vigilance is the price of beach freedom.