I started toward the house, but he didn’t follow, so I turned to face him. The sun was directly overhead and he shaded his eyes with one hand. “What did you think in the beginning?” he said.

The sandy ocean floor was warm and gluey under my feet. “I thought it was honesty, loyalty,” I said, thinking: fidelity. It was a betrayal, talking this way.

“You don’t think a little secrecy is good for the soul, the way a good scare is good for the heart?” He searched my face, but I made my expression blank. “I thought it was honesty, too,” he said. “I also thought it was timing, like if the right woman had come along when I was twenty-three, I couldn’t have held on until I was ready.”

I knew he wanted me to ask, but I stayed quiet.

“You know what I think the secret is now?” he said.

“Money?” I said. “Riches?”

“No, but you’re close.” He picked up a stone and threw it—not the way one would throw a stone to make it skip, but as if he were throwing it away. He seemed serious in the way that children sometimes are, and I thought he was one of the most intense men I’d ever known. “The man has to love his job. Show me a man who loves his job, and I’ll show you a happy home life.”

I was relieved. “You love your job.”

“Goddamn right I do. I spend my day with plants and people who take care of plants.” He paused. “Dennis doesn’t love his.”

“Not always.” I thought of Dennis’s one-window office, his apathy toward litigation and resentment of office politics. He’d spoken many times of leaving law for teaching or consulting. Before Paul said what he said—about a happy career begetting a happy marriage—I’d thought only of the pay cut.

I started to walk toward the house, and Paul followed for a few minutes, then moved beside me and matched my strides. When the water was ankle-deep again and the sea life thick, we slowed down. The house was a solid, three-dimensional place now, with a line coiled on the eastern square of the dock and a book spread open on a chair on the porch. We waded into waist-deep water and I dove beneath the surface and swam toward the house in a burst. I pulled myself up the ladder, feeling the water slide off my skin into the sunlight. At the top, I turned to check on Paul, and found that he was right behind me, his face inches from my thigh. I twisted away, but his hand landed on my ankle. “Wait,” he said.

I maneuvered out of his grip until I was seated awkwardly on the dock, a puddle staining the wood around my body. Paul sat beside me and touched the hem of my T-shirt. “What is this?” he said. There was a bruise the size and color of a sea urchin on my hip; part of it peeked out of the edge of my swimsuit. I’d chosen my longest T-shirt to cover it. That morning, when I’d noticed the bruise, it occurred to me it might be a harbinger of something horrible, like leukemia, but then I realized where the bruise was from: the night before, with Dennis, against the porch railing. It hadn’t felt so forceful at the time.

I pulled down my T-shirt. “I’m a klutz,” I said. “It happened yesterday, at the marina.”

Paul stared at me. “I heard you last night, you and Dennis.”

I had no response, but he didn’t seem to want one. There was a commotion in my peripheral vision.

“Holy shit,” said Paul. We stood and ran to the far end of the dock. In the spot where we’d last seen the white package, there was a splash. Something sliced through the water’s surface and submerged: a black fin. A second later, the water was empty and still.

“That was way too big for a nurse shark,” said Paul.

“Just what we need in this channel,” I said. “A great white on cocaine.” At this, what had been pulling at us seemed to snap, and we laughed. Paul went to the boat to get another pair of binoculars, and I went upstairs to make lunch.

That night, we played poker in the living room after supper. It was Marse’s idea—she said it would take her mind off her sunburn. We sat on couch cushions around the coffee table. We drank red wine and talked about Dennis and Marse’s fishing trip—they’d caught three snappers and a grouper, all of which we grilled for supper—and about what Paul and I had seen. The morning’s drama appeared to have reached its conclusion, and we were resigned to never knowing the contents of the package or its intended recipient. Marse suggested we tell the Coast Guard about the shark—wouldn’t people want to know there was a large shark in the bay?—but Paul said maybe it wasn’t as large as it seemed, and Dennis said it probably had gone straight back out to sea, where it came from. There was a lot of conjecture about what drug would most tempt a shark, and what kind of shark it most likely was, black tip or bull or lemon. I wondered if the incident should make me feel less safe in the water, but in the end, I felt it was just something that had happened and would not happen again. I was glad that we would all return to Miami with a story to tell.

We were so far from shore, so far from civilization. There was only the slap of the waves, so steady that the sound disappeared into the atmosphere the way cricket cries do in summertime, leaving human sounds to punctuate the night: laughter, jeers, the sliding of cards and change across the coffee table. Paul won fourteen dollars and I won eight. “What do you say we make a run for it?” said Paul. His eyebrows were thick and dark in the candlelight; the swells of his face cast shadows on the hollows.

“Don’t mind him,” said Marse, slapping his thigh. “Just say, ‘Down, boy,’ and he’ll behave.” She stood and yawned with her arms over her head. We all watched her; the moment expanded. “Bedtime,” she said. I went to help her move the mattresses. When I came into the bedroom, she said, “Maybe we should split up for tonight. Would you mind if we slept on the porch? Or you two could sleep out there and we could take the master?”

Her tone was aloof. I said, “We’ll take the big bedroom, and you take the porch. It’s no problem.”

“Good.” She pulled a mattress from the bed and turned it on its side, then started to drag it across the linoleum toward the doorway. I was in her way, so I moved, and though she looked as if she could use some help, her manner suggested that she did not want any. At the door, she stopped and her shoulders sagged.

“Marse?”

She tipped the mattress over and it landed with a soft thump. “Paul can deal with this,” she said. She left the room and I stood there alone, wanting to pick up the mattress but knowing I shouldn’t. In the few years I’d known her, this was the second time I’d stood in that very room feeling as if I’d stolen something from her. I hadn’t, of course—not really. Not the first time, with Dennis, and not now, with Paul, who I assumed flirted with all of his friends’ wives. Nevertheless, I was astonished to find myself back in this situation. I thought, I’m not even the pretty one. This was not false modesty. In a room full of men, nine out of ten would have chosen Marse over me for a fling or more. She was thinner, with a more fashionable hairstyle and better clothes, and she was more self-confident. For whatever reason—and I don’t deny that it might have been something I was doing, some competitiveness I didn’t want to acknowledge—I’d attracted, twice, men she’d claimed as hers. And I knew that if I wasn’t very, very careful, I would lose her over it. I might have lost her the first time, but she’d been gracious. The possibility of losing Marse—even then I knew that she could be my friend for life, this obstacle notwithstanding—was unthinkable to me.

I slept uneasily, and dreamed about playing poker. In the dream, I felt the queasy satisfaction of a person who wins by cheating, though I didn’t know how I’d managed it. I collected my money—stacks of torn and faded green bills—and when I looked up to face my opponent, I saw that I’d been playing against a grown-up Margo. Her freckles had receded and her chin was sharp like Dennis’s mother’s; there was a beauty mark on her neck. I’d never before imagined so clearly what she might look like when she was older.

I woke Dennis by saying his name until he opened his eyes and looked at me, appearing not curious or irritated, but matter-of-fact, as if he’d been listening all along. I whispered, “Why didn’t we bring her? We could have brought her.”

“We needed some time alone,” he said in his gruff half-asleep voice, sounding unconvinced.

“We’re not alone.”

“We’re with adults. It’s different. We’ll bring her next weekend.” His face was no more than an inch from my own. He said, “Aren’t you having a good time?”

I didn’t want to say no, but to say yes would have been a lie. I understood that for whatever reason, I wasn’t made for this kind of weekend, two couples on an island. I was too consumed by every little thing; it would’ve been impossible for me to enjoy myself. “It’s gone well,” I said, and felt Dennis relax. There would come a time, long after he and Paul were no longer friends, when I would tell Dennis that Paul had noticed my bruise. I would transform the story from what it was—discomforting but also thrilling—into just another anecdote. Did he watch us? Dennis would say. Or did he hear us from bed? Maybe he’d gotten up for a glass of water, I would say. Maybe he heard us sneaking back to bed and guessed where we’d been.

I never told Dennis what I believe happened, what I imagine when I recall the scene: Paul heard us rise from bed. He followed us. He stood in the kitchen window the entire time, watching us—watching me—from the darkness.

We were standing on the dock, getting ready to head out to Soldier’s Key for some snorkeling, when the Cessna returned. It was late morning, and we’d eaten breakfast and packed up in anticipation of leaving that afternoon. Dennis shushed us. “Listen,” he said.