I AND SHELTON untied the lines. Ben eased Sewee back from the dock and into open water. “Next stop, Dewees Island.”

I tried to shake off the horrid news about the Fletchers. I’d process my feelings later. Right then, we needed to focus more than ever.

“So what do we know?” I asked.

The boys snapped to attention, no doubt sharing the same mixed feelings.

Hi referred to his omnipresent iPhone. “Dewees is north, between Isle of Palms and Bull Island.”

“Former Sewee country,” Ben added. “My ancestors used to visit Dewees as well as Bull. Its real name is Timicau.”

“I remember we passed it last night,” I said. “Not many lights.”

“Dewees is a very eco-conscious community,” Hi said. “Small, and extremely pricey. The island is one unified design, and ninety-five percent of the land will never be developed.”

Shelton chimed in. “Twelve hundred acres, so it’s less than a third the size of Bull. No bridge, and no cars. The only link is the Aggie Gray ferry running from IOP.”

“That’s twice I’ve heard no cars.” Ben steered into Charleston Harbor, heading north for the Intracoastal Waterway. “How do they get around?”

“Golf carts.” Hi answered. “Private gas-powered vehicles are prohibited. It’s a sleepy place. No restaurants. No grocery stores. No gas stations. Dewees is like a wildlife preserve, except rich people have vacation homes there.”

“Great,” Shelton said sarcastically. “Untarnished natural beauty. That means more swamps, bugs, and giant gators. And we’ve got no idea what we’re looking for.”

I ignored him. Mainly because he was right.

Conversation died, and I sensed the boys’ thoughts returning to the Fletchers. I spoke to keep their attention on the task at hand.

“What else is on the island?”

“Besides private homes? Not much.” Hi rattled off a list. “A small lodge, a firehouse, two public-works buildings, a canoe shelter, an old church, scattered fishing docks. Commercial activity is essentially banned.”

Shelton couldn’t sit still. “You really think somebody killed them?”

Ben gave him a “let it go” look. “So where do I tie up?”

“Wherever,” Hi said. “The whole island is private property, so we’re trespassing regardless.”

Ben forced a smile. “One thing we’re good at.”

We circled the southern edge of Sullivan’s Island and entered The Cove, passing the Claybourne cabin for the third time in two days. Dewees lay several miles up the waterway.

“Guys.” Shelton’s voice sounded tight. “Is that boat following us? It pulled out quickly, right after we passed Chance’s place.”

Three heads whipped around. A hundred yards behind us, a second vessel trailed in our wake.

“Looks like two people,” Hi said. “But I can’t be sure.”

“It’s a summer day in Charleston,” Ben replied. “Dozens of boats must be using the waterway.”

Nonetheless, he increased our speed.

“Easy,” Hi cautioned. “We’re in a ‘no wake’ zone.”

“You think I don’t know that?” Ben glanced back over his shoulder. “Tell me if they keep pace.”

Tense minutes passed. The other vessel failed to fall back.

“Crap.” Ben checked Sewee’s dials. “I’m pushing the limit, but they’re keeping pace. That boat sped up when I did.”

“Doesn’t sound like Beau and Buffy out for a pleasure cruise,” Hi said.

Shelton grabbed for an earlobe.

We passed beneath a bridge and the waterway narrowed. Head-high spartina lined both sides of the channel.

“Hang on.” Ben down-throttled and Sewee kicked forward. “There’s less traffic around here, so I’ll risk a fine.”

We surged forward. The trailing boat grew smaller, gradually disappeared.

“Can we can lose them for good?” I asked.

Ben nodded. “If someone’s following us, they probably think we’re headed for Bull Island again, right?”

“Makes sense,” I said. “This is the same route we took last night.”

“There’s an islet south of Dewees called Big Hill Marsh. I’ll cut through Bowers Creek and hide Sewee behind it. If that boat is headed to Bull, they’ll go right by and never see us.”

We tore up the waterway, splashing illegal wake, eyes peeled for signs of pursuit. Minutes later we reached the northern tip of Isle of Palms.

“That’s the islet.” Ben pointed straight ahead to a low green atoll. Steering hard to starboard, he entered a narrow creek, rounded the tiny landmass, and cut the engine. “Keep quiet.”

For several minutes, we heard nothing but screeching gulls.

Then, the distant buzz of an engine. The noise increased, and for a tense moment seemed right on top of us. But the boat passed and the engine sound receded.

We exchanged nervous smiles.

“No sweat,” Ben said.

“Probably just two dudes going fishing,” Shelton joked.

After a cautious interval, Ben cranked the motor and we rounded Big Hill Marsh. Dewees Island appeared ahead, its dock a fuzzy blur in the afternoon sun.

I shot Ben a thumbs-up.

“Take us in, captain.”