There are eighteen passengers on the boat, all slightly caricatured representatives of a variety of social backgrounds, ranging from the top end of the working class to the low end of the power elite. The tough guy Atilio Presutti (nicknamed Pelusa), whose brother is a popular tango singer, is accompanied by his girlfriend, Nelly, and their two cliché-spouting socially ambitious mothers. At the other end of the scale, Don Galo Porriño, a wealthy merchant of Gallic descent, travels in a wheelchair with his chauffeur in constant attendance. López and Doctor Restelli teach at the same school, although they represent quite different social and political points of view: Restelli is a reactionary dandy who quickly allies himself with the peace party, while López is a bohemian leftist who drinks beer with his students and joins the ranks of the malcontents. Felipe Trejo, one of the less popular students at the same school, has invited his nasty, spoiled little sister along as well as his unctuously snobbish parents. Claudia Lewbaum, divorced from a neurologist, and her son Jorge have invited the absentminded and slightly crazy intellectual Persio to accompany them because they fear for his health. The two other couples are so unalike that they seem deliberately contrasted. Lucio and Nora, desperately but conventionally and even grotesquely in love, have recently eloped and are worried about the reaction of her respectable parents. Paula and Raúl share a platonic but genuine friendship.
Several of the male members of the radical group are roughly of the age and political views of Cortázar. At least two of them—Medrano, the intellectual haunted by the temptation of political involvement, and Persio, avant-garde aesthete and literary theorist—may be seen as expressing central concerns of the author. Yet none of the characters escapes the generally ironic tone of the narrative or the invariably parodic tone of the dialogue.
It is impossible to avoid the impression that the narrowness of vision of a whole society is being suggested. The situation of the passengers, manipulated by arbitrary and remote authority, leads some to attempt to find answers, while most are quite content to accept what they are told. Even those who actively seek the truth compromise in the end, however, and their efforts and sufferings are seen to be empty.