"Take the wheel," I said.

I saw her thoughts gathering in her face.

"We didn't refill the air tanks last time," she said.

"There's still some in there. It's not more than twenty-five feet here, anyway. If they haven't settled into the silt, I can get the doors open."

"Dave, it's deeper than twenty-five feet. You know it is. There's a trench right through the Pass."

I got the two air tanks out of the gear box and looked at the gauges. They both showed almost empty. I stripped down to my skivvies, hooked on a weight belt, put on one air tank and a mask, and slipped the canvas straps of the other tank over my arm. I picked up a crowbar out of the gear box.

"Anchor outside so one of them doesn't come up under the boat," I said.

"Leave the other tank. I'm going down, too." She had cut back the throttle, and the boat was pitching in its own wake. The side of her tanned face was wet with spray, and her hair was stuck to it.

"We need you up here, babe," I said, and went over the side.

"Damn you, Dave," I heard her say just as I plummeted with a clank of metal tanks through the water's surface.

The bottom of the Gulf was a museum of nautical history. Snorkel and scuba diving over the years, I had found clusters of Spanish cannonballs welded together with coral, U.S. Navy practice torpedoes, and the flattened hull of a Nazi submarine that had been depth-charged in 1942, a cigarette boat that dope runners had opened the cocks on before the Coast Guard had nailed them, and even the collapsed and twisted wreckage of the offshore oil rig on which my father drowned over twenty years ago. It lay on its side in the murk in eighty feet of water, and the day I swam down to it the steel cables whipped and sang against the stanchions like hammers ringing against an enormous saw blade.

The plane had settled upside down on the edge of the trench, its propellers dug deep in the gray sand. Strings of bubbles rose from the wings and windows. I felt the water grow colder as I went deeper, and now I could see crabs and jewfish moving quickly across the bottom and puffs of sand from the wings of stringray that undulated and glided like shadows down the sides of the trench.

I got down to the pilot's door, slipped the spare tank off my arm, and looked through the window. He stared back at me upside down, his blond hair waving in the current, his sightless green eyes like hard, watery marbles. A short, thick-bodied woman with long black hair was strapped into the seat next to him, and her arms floated back and forth in front of her face as though she were still trying to push away that terrible recognition that her life was about to end. I had seen drowning victims before, and their faces had had the same startled, poached expression as the faces of people I had seen killed by shell bursts in Vietnam. I just hoped that these two had not suffered long.

I was kicking up clouds of sand from the bottom, and in the murky green-yellow light I could barely see through the window of the back door. I held myself out flat, holding on to the door handle for balance, and pressed my mask to the window again. I could make out a big, dark man in a pink shirt with pockets and cloth loops all over it, and a woman next to him who had floated free from her seatbelt. She was squat, with a square, leathery face, like the woman in front, and her flowered dress floated up around her head. Then, just as my air went, I realised with a terrible quickening of my heart that somebody was alive in the cabin.

I could see her small, bare legs kicking like scissors, her head and mouth turned upward like a guppy's into an air pocket at the rear of the cabin. I dumped the empty tank off my back and jerked on the door handle, but the door's edge was wedged into the silt. I pulled again, enough to separate the door a half-inch from the jamb, got the crowbar inside, and pried the metal back until I felt a hinge go and the door scrape back over the sand. But my lungs were bursting now, my teeth gritted against my own exhalation of breath, my ribs like knives inside my chest.

I dropped the crowbar, picked up the other tank, slapped the valve open, and got the hose in my mouth. The air went down inside me with the coolness of wind blowing across the melting snow. Then I took a half-dozen deep hits, shut the valve again, blew my mask clear, and went in after her.

But the dead man in the pink shirt was in my way. I popped loose his seatbelt buckle and tried to pull him free from the seat by his shirt. His neck must have been broken because his head revolved on his shoulders as though it were attached to a flower stem. Then his shirt tore loose in my hands, and I saw a green and red snake tattooed above his right nipple and something in my mind, like the flick of a camera shutter, went back to Vietnam. I grabbed his belt, pushed under his arm, and shoved him forward toward the cockpit. He rolled in a slow arc and settled between the pilot and the front passenger seat, with his mouth open and his head resting on the pilot's knee, like a supplicant jester.

I had to get her out and up fast. I could see the wobbling balloon of air she was breathing out of, and there wasn't room for me to come up inside of it and explain what we were going to do. Also, she could not have been more than five years old, and I doubted that she spoke English. I held her small waist lightly between my hands and paused, praying that she would sense what I had to do, then dragged her kicking down through the water and out the door.

For just an instant I saw her face. She was drowning. Her mouth was open and swallowing water; her eyes were hysterical with terror. Her close-cropped black hair floated from her head like duck down, and there were pale, bloodless spots in her tan cheeks. I thought about trying to get the air hose in her mouth, but I knew I wouldn't be able to clear the blockage in her throat and she would strangle before I could get her to the top. I unhooked my weight belt, felt it sink into the swirling cloud of sand under me, locked my arms under her chest, and shoved us both hard toward the surface.

I could see the black, shimmering outline of the jug boat overhead. Annie had cut the engine, and the boat was swinging in the current against the anchor rope. I had gone without air for almost two minutes, and my lungs felt as though they had been filled with acid. I kept my feet out straight, kicking hard, the bubbles leaking through my teeth, the closure in my throat about to break and suck in a torrent of water that would fill my chest like concrete. Then I could see the sunlight become brighter on the surface, like a yellow flame dancing on the chop and glazing the flat slicks, feel the layers of current suddenly become tepid, touch the red-brown wreaths of seaweed that turned under the waves, then we burst into the air, into the hot wind, into a dome of blue skies and white clouds and brown pelicans sailing over us like welcoming sentinels.

I grabbed the bottom of the deck rail with one hand and held the little girl up to Annie's arms. She felt as though she had the hollow bones of a bird. Annie pulled her up on deck and stroked her head and face while the little girl sobbed and vomited into Annie's lap. I was too weak to climb out of the water right away. Instead, I simply stared at the red handprints on the child's trembling thighs where the mother had held her up into the pocket of air while she herself lost her life, and I wished that those who handed out medals for heroism in war had a more encompassing vision about the nature of valor.

I knew that people who took water into their lungs sometimes developed pneumonia later, so Annie and I drove the little girl to the Catholic hospital in New Iberia, the small sugar town on Bayou Teche where I had grown up. The hospital was a gray stone building set in Spanish oaks on the bayou, and purple wisteria grew on the trellises above the walkways and the lawn was filled with yellow and red hibiscus and flaming azalea. We went inside, and Annie carried the little girl back to the emergency room while I sat across the reception desk from a heavyset nun in a white habit who filled out the girl's admission form.