Marty left the pilothouse and transferred fourteen hydrophones from the ship’s workshop to the aft deck. They were cylindrical, made from ceramic so as to not interfere with the reception of audio input, and mounted on stainless steel cones to keep them from touching the seabed. Chunky waterproof battery packs allowed them to record the first two minutes of acoustic data every ten minutes for up to three months. Over the next few hours, he used the A-frame boom to deploy four of them in a vertical line array at a depth of 150 meters.

At five o’clock he called it a day and went below deck to shower and change into evening clothes. When he returned to the main deck, he found everybody gathered and talking excitedly. It took him a moment to realize what all the fuss was about: a curlicue of smoke rising from the center of Demon Island into the darkening twilight.

Brow furrowed, he said, “I thought the island was unpopulated.”

Elsa nodded. “It’s a designated wildlife sanctuary.”

“That’s what I read. So who’s that over there? A ranger?”

“Or a castaway,” said Rad. “That could be an SOS smoke signal.”

“At nighttime?”

“I’m with Marty,” Jacky said. “It’s simply some ranger cooking his dinner.”

“Looks like a lot of smoke for a cooking fire,” said Rad.

“You know, that island used to be used as a prison of sorts?” Marty said, deciding to have some fun with Rad, knowing she was superstitious to her core. “At the beginning of the eighteenth century a Dutch soldier was convicted of sodomy while stationed in what was then Ceylon. He was marooned on Demon Island as punishment. Perhaps his ghost still haunts it?”

“Ghosts don’t make fires.”

“Perhaps it uses the smoke to lure unsuspecting sailors to the island?”

Rad folded her arms across her chest. “You’re not scaring me, Marty. You’re being condescending.”

Grinning, Marty lit his pipe, stuck the stem in the corner of his mouth, and puffed. “I’m going to make myself a much-deserved drink,” he announced. “Would anyone care to join me?”

∆∆∆

Earlier in the day Marty had caught several bony fish on trolling lines. He baked two of them—a mullet and snapper—for dinner, which everybody ate on the foredeck. Afterward they sat around beneath the stars for a nightcap. Jacky and Rad chatted with Pip, while Marty and Elsa had an erudite discussion on the acidification of the oceans. Nobody seemed in the mood to talk about merfolk, Marty included, and at seven thirty they retired to their cabins for an early night.

Marty dreamed he was lost on Demon Island, pursued by creatures he couldn’t identify. He woke before dawn, sheathed in sweat. He showered, shaved, dressed, then went to the dry lab to check on the preliminary data from the hydrophones.