She sank into a trough. The strobe might be very near, or might not. She lost her fatigue. As she dropped, treading water, she pirouetted, searching the rim of her moving canyon.

There was nothing. She rose again, flailed her body full-circle around before she sank, spitting, into the next trough.

She must have imagined the flash. Her pace had been too listless all night long to have brought her anywhere near. There was no hope, she was simply losing her mind, from fatigue and fear and thirst.

The rim of her surging valley lit suddenly. A white-plumed breaker, caught slipping over its crest, posed starkly as if trapped by a flashbulb.

She yelled with joy and shipped a mouthful of water. She found herself thrashing up the side of the swell, against an avalanche of white water bearing down on her. She lost the plastic container, which swept down the gulf behind her. She did not care.

She crested the swell. She sank in the next, and rose, and sank again, and all at once was blinded by an immense white flash directly ahead.

She was suddenly in total darkness. She had lost her night vision. She could see no stars, no waves. She squinted, dreading the next explosion of light.

But when it came, she was ready. The strobe flashed, leaving imprinted on her after-vision its little orange cylinder and, much more, the man-overboard flag frozen in full-flutter on the side of a swell, and the bright yellow horseshoe-buoy, all attached to each other by a yellow line caught snaking up the wave.

She floundered for the horseshoe-buoy. There was another searing flash to her left, before she reached it. She lunged blindly, felt the slippery plastic cover of the buoy, and lost it again in the rush of water off the crest of a swell. She took two brave strokes downhill into the white foam and snatched the buoy tumbling down the slope.

She lifted it over her head, worked her arms through, and snapped the stainless cable across its open end.

She had swallowed too much water, and now she gagged. She kept slipping through the horseshoe because her arms were too tired to stay up on the rim. And, relieved of the need to kick, she was cold again in minutes.

She had little hope that he would spot the flag at dawn. She doubted that she could hang on until then, anyway.

There was much more hope in the flash, if only he would hurry.

All night long she had waited for morning. Now she wished that it would never come.

For four hours he had been zigzagging, back and forth, over his wake. This was the area, if his navigation and the logbook were right, where she had fallen. Now that the logbook had told him this, the dark swells seemed more threatening.

He teetered on the coaming, steering with one foot, letting the necessity to balance keep him awake.