The narrator, while at the beach, is seduced by an ocean wave, which begs to be taken home with him. He tries to explain that she would not like life in the city, but she insists. To bring her home on the train, he empties the drinking fountain tank and secretly pours the wave into it. But when a lady takes a drink and discovers that the water is salty, her husband calls the conductor over, accusing the narrator of contaminating the water. The conductor calls in the Inspector, who calls the police, who accuse the narrator of poisoning the water. The police then call in the Captain, who calls three agents. The agents take the narrator away and throw him in jail where he is interrogated and accused of trying to poison the children on the train. After a year in jail, he is tried and, soon after, set free.
When the narrator arrives home, the wave is already at his house. She explains that someone had poured the ‘‘contaminated’’ water from the drinking fountain onto the engine, where she became steam and, as such, rode the train the rest of the way to Mexico City.
The narrator states that the wave’s presence in his home ‘‘changed my life.’’ He carries on a passionate love affair with the wave, to whom ‘‘Love was a game, a perpetual creation.’’ Her moods are as changeable as the tide, and she engulfs him with her love. When the wave complains that she is lonely, he brings her seashells and toy ships to wreck; but this is not enough, and he brings her a colony of fish to play with. However, he soon becomes jealous of the wave’s attentions to the fish. One day, he ‘‘couldn’t stand it anymore,’’ and tries to attack the fish; but the fish slip through his fingers, and the wave sucks him under her water and nearly drowns him. Although she is affectionate and apologetic afterward, he begins ‘‘to fear and hate her.’’
After this incident, the narrator realizes that he had been neglecting his other responsibilities. He begins to stay away from home more, to see old friends, and even to meet with an old girlfriend. He tells her of his troubles with the wave, and she wishes to help him, but there is nothing she can do.
As their relationship deteriorates, the wave becomes petulant and brooding. With the onset of winter, she grows increasingly angry and violent, bringing forth ‘‘monsters from the deep.’’ Unable to stand her any more, the narrator flees to the wilderness in the mountains, staying away for a month.
By the time he returns, the weather has turned so cold that the wave has frozen into ‘‘a statue of ice.’’ Without feeling, he puts the frozen wave into a sack and takes her to a restaurant on the outskirts of the city, where he sells her to a waiter friend who immediately chops her up into small pieces, and puts the ice in buckets for chilling bottles of refreshments.