CLARA HAD BEEN CLINGING to the float for two hours. She no longer yelled or cried or paddled toward the retreating island. She lay with her eyes squeezed shut, her body as stiff and unmoving as one of those bodies uncovered in Pompeii, petrified in a moment of fear.

The waves were high and choppy now, and there was no rhythm to the movements of the float. It was like an amusement park ride designed to keep people off-balance. The float went up, turned sideways, tipped, was hit broadside by waves, slid between waves—up, down, sideways.

Occasionally when the float made a particularly wrenching move, Clara would moan, but it was the sound of someone beyond hope. She had long since given up any thought of rescue. She felt as if she had been drawn far away from the normal world, into one of those spots that sailors fear, where the sea ignores the laws of nature and goes wild, a spot marked on old maps by drawings of dragons and reptiles.

Clara had no idea how long she had been on the raft—all her life, it seemed. The part of her life spent on dry land—walking, sleeping, eating, doing normal things—seemed like a brief vague dream. This was hard cold reality.

A wave slapped against the float, and Clara suddenly felt it tipping over. She screamed and clutched the raft tighter, but her scream was cut short. The raft flipped over and Clara was thrown into the sea.

Her head went under water, and she came up choking. She slung her wet hair from her face and looked around. The float was drifting away.

Clara swam after it. She reached out. The current pulled the float just beyond her grasp. She struggled through the waves, her eyes on the float, gasping for breath, swallowing saltwater.

Her fingers touched the corner of the float and she fumbled to hold it. The float slipped away on the crest of a wave. She touched it again. It was gone. It was as if a playful hand were jerking the float out of her reach.

Clara began to swim. Another wave rose and she sank into the trough between waves. The float was out of sight. Clara was gripped with a terrible fear.

She waited, treading water anxiously, her eyes on the rolling waves. She caught sight of the float then, on the crest of a wave, and she struck out. Her arms and legs moved with a strength she had not known she had. Her teeth were clenched, her mouth clamped shut. A wave hit her face, and she plunged through it. She was gaining.

She swam again, lifting her head. The float was within reach. She scissored her legs in one last spurt and felt her fingers close on the thin plastic. Tears ran down her cheeks as she pulled herself up.

She lay across the float for a moment, her legs trailing in the choppy water. She coughed. She was exhausted. Her strength had gone as quickly as it had come. She could not lift her legs onto the float.

As she lay there, arms and legs trembling with fatigue and cold, she noticed something printed on the float. She blinked her eyes to clear them, NOT TO BE USED AS A LIFE PRESERVER, she read. She rested her face against the letters. Now they tell me. She closed her stinging eyes.

Then slowly, gasping with the effort, she threw one leg over the float. She rested. She pulled the other leg up and stretched out as gingerly as an old dog. She closed her eyes. Her heart was pounding in her ears.

She lay there, clutching the sides of the float with both hands, legs shaking, knees knocking, waiting tensely for the next wave that could throw her again into the sea.

This time, she said through her clenched teeth, this time I won’t let go.

She glanced over her shoulder. The waves were tinted red by the sinking sun. She glanced skyward. The clouds were moving in, gray and foreboding. A lone gull, white as snow, dipped in the darkening sky.

I will not let go, she said again.