He held up the other masks proudly. They were larger, designed to come all the way down over the chin, sealing around the neck, and had an airflow unit built into the faceplate. They looked like the kind of apparatus firefighters wear.

“No mouthpieces to bite down on,” he said, as if reading my thoughts. “And you can talk. There’s a radio link to earpieces we can all wear and to Archimedes here on the boat.” The captain gave a mock salute and a little grin. “It’s all perfectly safe. The water is not super deep, so you don’t need to worry about pressure, and you can toggle between your tank and the ambient air when you surface, so you don’t need to take the mask off at all once you have a good seal. We’ll all stay together. If anyone feels light-headed or disoriented, or you otherwise think you aren’t getting enough air, you tell Archimedes and he’ll give you this.” He indicated another, smaller tank. “Three liters pure O2. Emergency use only. OK? Let’s do this.”

The boat’s engine rumbled, blew out a puff of brown smoke, and came to life. Archimedes cast off and we began chugging out of the harbor. I caught Marcus watching me and gave him a brave smile over Simon’s shoulder as he walked me through my equipment and helped fasten the air tank to my back. It felt clumsy, doubly so with the ridiculous fins on my feet, and I felt both absurd and scared. Melissa and Brad were, predictably, as much in their element as Simon, trading stories of wreck dives and shark sightings in Mexico and Costa Rica. Kristen looked wary but game, and Marcus, apart from his concern for me, seemed happy to at least try. The only person who looked as uncomfortable as I felt was Gretchen, and I found myself warming to her a little.

“You OK?” I asked.

“Not much of a swimmer,” she said under her breath, thumbing absently through a homemade picture book of the creatures we might see that Archimedes had given her. “Or sailor,” she added.

“Oh,” I said, making a sympathetic face. We had barely left the dock, and she already looked a little green and was sitting very still, as if refusing to move at all would compensate for the bouncing of the boat’s nose on the water.

“I’ll stay close,” I said.

She managed a smile.

“Thanks,” she said. “Do you do this a lot?”

“First time,” I said, resisting the impulse to lie and then, as her smile stalled, wishing I hadn’t.

“You think it’s safe?” she said. “I’m not sure I should really be trying this in the ocean. Shouldn’t we have training first? In a pool?”

“Simon knows what he’s doing,” I said.

She nodded, watching him, but murmured, half to herself, like it was a mantra, “I’m really not a strong swimmer.”

“It’s just kicking,” I said. “You don’t have to work to keep yourself afloat. The gear gives you a kind of neutral buoyancy, so you just pick the direction and go.”

“I thought you didn’t know anything about this stuff?” she said. Her nervousness gave the remark a sharpness and her eyes were faintly accusatory, as if I had misled her on purpose.

“My sister does it,” I said. “Loves it. She’s always trying to talk me into joining her.”

“Family Thanksgiving under the sea,” said Gretchen mirthlessly.

“Oh, I won’t be seeing her this year,” I said. “She lives in Portland. We don’t connect much.”

“Had a falling out?” said Gretchen, pleased by the idea of something else to talk about. Or by someone else’s unhappiness.

“You could say that.”

“Over what?”

I looked away.

“Go on,” said Gretchen with a pleading smile. “Take my mind off being about to drown.”

I smirked at her, then shrugged.

“Nothing exciting,” I said. “What sisters always fight over, I expect. Our parents. Who loves whom most. Who’s doing the other person’s share of the work, the care, the worry. The usual.”

“What line of work is she in?”

“Software development for movies,” I said. “CGI and such.”

“Ooh, fun,” said Gretchen, managing a real smile for the first time since the boat hit open water.

“You’d think,” I said. “She spends most of her time talking about how companies are constantly shopping for cheaper labor. The people who actually do the work don’t get to stamp the finished product with their name and face like actors do, so it’s hard for them to demand what they’re worth when less-skilled companies elsewhere are prepared to do the job for less. And then the studios are constantly adding work to the contract—more scenes, more edits—and expect not to have to pay extra. CGI takes time so the work starts early, but then the script changes or the director goes in a different direction, and all the digital work that was already done is useless and has to be scrapped, but the contracts are structured so that the studios don’t have to pay for anything but finished product. It’s a mess.”

“Sounds like you know a lot about it,” said Gretchen, impressed.

“About as much as I do about scuba diving,” I said. “I can tell you what Gabby—my sister—bitches about, but ask me to add a troll to a battle scene, and I’d be drawing on the film with a Magic Marker. Let’s hope my diving is better.”

“Stay close to me,” said Gretchen. “We’ll drown together.”

“Terrific.”

Archimedes doubled as gear tech as well as captain, and we spent twenty minutes or more being poked and scrutinized once the boat came to a halt. He was a big guy, a decade older than the rest of us, broad shouldered, strong, and tanned to the color of tea. His black hair was silvering at the temples and he was developing a gut. He smelled, not unpleasantly, of sea and sweat and oil. As he tightened the straps around my tank, he managed to be careful not to brush against my body while still giving me a mischievous look that reminded me of the awkwardness of being so close to a strange man while wearing very few clothes.

“Now this,” he said, giving me the mask Simon had already shown me. He guided it over my face and inspected the seal. “Breathe OK?” he asked.

I tried, feeling hot and claustrophobic, my peripheral vision lost, and nodded.

“Talk,” he said, pointing at his mouth. “You can talk.”

“Oh,” I said. “Yes. I can breathe.”

Talking and breathing at the same time was hard, and I had to pause, feeling my heart racing, to steady my nerves. I took longer, slower breaths and felt better. Archimedes took my hand and guided it to the airflow regulator in front of my mouth.

“This air,” he said, gesturing vaguely at the sky, then turning the switch. “This tank. OK?”

I nodded.

“Talk,” he said.

“OK,” I said. “Yes.”

I wished I could see. The scuba gear was handicap enough without me being close to blind to begin with.

“If you like this,” said Simon, “we could come back. There’s a World War II German fighter farther out. A Messerschmitt. That would be pretty cool, right?”

“A 109?” asked Marcus, clearly excited.

“How the hell should I know?” Simon quipped. “What do I look like, a historian?”

“Could be a 110, I guess,” Marcus mused. “Or a Focke-Wulf. A 109 would be neat, though.”

“Whatever, professor,” said Simon. “It’s an old plane. Who cares what kind?”

I looked at him through the diving mask, and it was like I wasn’t really there or was watching the scene on television, so I could do or say anything I wanted and they wouldn’t know. The effect gave me an oddly critical distance. Simon was joking, boisterous and grinning in a matey way, but the remark had that casual unkindness he and Brad so easily slipped into. It wasn’t malicious exactly, just dismissive, as if there were a line between what was cool and what was dorky that they instinctively recognized. People like Marcus were always straying over it. For his part, Marcus shrugged the moment off, laughing at himself, and I couldn’t tell if he felt stung.

We hadn’t actually gone far from the boathouse—a half mile, perhaps, maybe less—and I found myself both relieved and disappointed. Not that I could see the shore, but Gretchen kept checking. Everything was a blurry vagueness to me, and I suddenly wondered if that would also be a safety hazard on top of making the whole expedition a bit pointless. I considered Archimedes, and as soon as he was finished with Melissa—clad today in a vivid yellow bikini worthy of Sports Illustrated—I got his attention.

“I’m sorry,” I said, still speaking through the mask to his earpiece, “but do you have any lenses? I left my glasses at home and . . .”

“Lenses?” he said, frowning at the word.

“My eyes are . . . not good, and . . .”

“Ah,” he said, holding up one hand and beckoning me over to the stern of the boat, where a series of plastic baskets were heaped with snorkels and life jackets. He pushed things around, grunting to himself, and came up with a box of single-piece goggle inserts. He pushed it over to me and pulled my mask back.

“Sorry,” I said. “Should have done this before. Sorry.”