The air was so still it was almost eerie.

Guided by the light of the moon and our curiosity for whatever was out there, my travel companions and I dropped our sandals and clothes on the dark beach and, in our swimwear, waded out into Gulf of Thailand.

We flung our arms and legs at the surf. We tried to churn the waves and stir them to life.

Then, suddenly: The beings were awake, and the darkness was broken, too. Millions of the tiny glowing plankton surrounded us. They clung to our legs and arms and we waded deeper, covering our bodies with mobile, shimmering suits. They lit up the water in bursts of white-blue luminance like a sea full of lightning bugs — the kind of natural light show we’d read about.

After a trek across crowded, tourist-filled Thailand, this felt like the perfect antidote. On the edge of a quiet fishing village on a Cambodian island, we splashed and heard our own shrieks and laughter echo along the jungle coast.

We felt lost, stranded. In the best way possible. Later, though, we would find that freedom came with the messy side effects of going off the grid.

The day had begun in Siem Reap. After two days in the charming city, my Belgian travel partner Mel and I flew to Sihanoukville, an emerging beachside paradise on Cambodia’s coast. Once there, we spontaneously hopped a ferry to Koh Rong Sanloem, the smaller of two nearby islands.

The boat dropped us off at Saracen Bay, a resort-line beach that has been quietly gaining steam as an off-the-beaten path retreat. But there was another option — M’Pai Bay, a fishing village farther down the shore. This was the true escape, a ferry worker had told us. We were in. A pair of Australian travelers whom we’d met while boarding our plane from Siem Reap decided to come along.

The trek to M’Pai Bay wasn’t immediately clear. The 9½-square-mile island was filled with dense jungle, save for the tourist beach, M’Pai Bay, and another tiny village. There were no roads, only a handful of sand paths along the beach hamlets. (It was especially amusing to a Cambodia native when we’d asked before arriving on the island if we could rent mopeds.)

After lunching at an ocean­side resort, we persuaded a water taximan sporting a long, shallow, wooden boat to take us there for $40. Packs on our backs, we waded thigh-deep into the warm, turquoise water and boarded our transport.

We arrived at a thin, concrete dock about an hour later. Around us, island peaks rose in the distance. Similar long, colorful boats floated in the bay. Houses and cafes, built onto the dock, were propped up on rickety-looking wooden pillars, but they had the appearance of surviving there for quite some time.

On the ferry to the larger tourist area, we’d hastily rented a hut for the next two nights. The simple structure, right on a beach, consisted of two cots covered with mosquito nets, a fan and a toilet that could be manually flushed with water scooped up from an adjacent barrel.

After Mel and I dropped off our bags there, we made our way to the Mango Lounge, the village’s bar, to reconvene with our Australian friends. Sitting on round tree stumps that served as stools, we listened to stories from the bartenders — most of them European — of how they’d come for vacation and never left, opting to spend the subsequent months and years in shorts and flip-flops, becoming ingrained with their new home by fishing, bartending, fixing things or, most often, all of the above. It had the feel of a shipwrecked community, pieced together by way of happenstance.

Outside the bar, patrons smoked in bamboo bucket seats with cushions that had been soaked in the saltwater air and drenching rains and dried again in the sun. A handful of other storefronts nearby, including a convenience store stocked with toilet paper and coolers of soda, spilled out onto the ankle-deep, dark sand. Life felt slow.

In a few hours, we would watch the sun sink over the rocks on Pebble Beach outside our hut, then head to dinner at a place called Fishing Hook. The dock restaurant, equipped modestly with communal tables and rugs to sit on, served a barbecued seafood and vegetable buffet for $6 a plate with one catch: Patrons were charged extra for any leftovers, preventing waste. That money, along with a dollar from each plate, went to the community medical center project.

It was a wonderful feast, and fuel for our subsequent plunge into the ocean filled with glowing plankton.

The dark side

But late in the night, after we’d gone to bed, we discovered that we’d been food-poisoned. My instinct was that the bad fare had come from the resort in the tourist area, not Fishing Hook, but we couldn’t be sure. (When we told the owner of Mango Lounge, he shrugged. “You’re in Cambodia,” he said. “What do you expect?”)

The rest of the night and the next morning, we were tormented. But we had another problem, too: We were out of money, and wouldn’t be able to pay for our hut (or our necessary ration of bottled water) without more. With no ATMs or credit card use available on the island, our only option was to boat to a neighboring island. It was a trip that could take as little as half an hour, but this afternoon, the winds were wild, and the excursion took over an hour. The swelling waves rocked us until our yellow faces were threatening to turn green. Mel, weak from the loss of fluid, tried to lie down on one of the long seating benches that ran down each side of the boat, but nearly spilled into the ocean on one dramatic crest and fall. The rest of the way we sat across from each other to balance the craft, white-knuckling the vessel’s shallow sides and mulling how long we’d be able to stay afloat in the surf if we fell out before the captain could turn around to rescue us.

When we arrived at the other island, soaked from water pouring into the boat, we were barely walking straight. We got the money and by miracle made it back.

The rest of the day was spent in our bunks, sweating in the 90-degree heat under the mosquito nets and manually flushing away each food sickness bout. It would take some time for the sickness to fully pass.

Even so, when we left the next day, our stomachs raw and bodies exhausted, the peculiar, almost magical aura of the place was still intact. The twinkle of the plankton that surrounded us, like Christmas lights to a tree, was still fresh in my mind.

Food poisoning or no food poisoning, I thought, it had been worth the trip.

After we swam with the plankton that first night, we had tramped back to the main beach in the lightless jungle. The village, which runs entirely on an electric generator that is shut off at midnight, had already been plunged into darkness. Guided by each other’s hands and the lights of our cellphones, we had found the one beachside hut bar — a noise-muffling distance from the main beach — that was still awake. Top 40 music from several years ago blared. Young tourists and locals drank gin and tonics from sandy plastic cups. Next to the structure, a bonfire roared. A couple of young men in T-shirts and baseball caps lit both ends of long sticks in the fire and twisted them in lightning-quick spins, snapping them over their heads and around their bodies.

The sparks flickered into the humid air, and I wondered if they were floating out to sea to mingle with their sparkling underwater counterparts.