Walking along a street in Venice, Antonio (the "merchant" of the title) confesses to his friends Salarino and Salanio that lately he has felt unaccountably sad. They have noticed it, and they suggest that Antonio is probably worried about the safety of his merchant ships, which are exposed to storms at sea and attacks by pirates. Antonio denies this and also denies that he is in love, a possibility that both of his friends think might explain Antonio's pensiveness. Salarino concludes that Antonio's moodiness must be due simply to the fact that Antonio is of a naturally melancholy disposition. At this point, their friends Bassanio, Lorenzo, and Gratiano join them, and after an exchange of courtesies, Salarino and Salanio excuse themselves. Gratiano takes a long look at his old friend Antonio and playfully chides him for being so solemn and so unduly silent. Gratiano says that he himself never has "moods"; in contrast to Antonio, Gratiano is determined to always "play the fool." Lorenzo intimates that sometimes Gratiano is too much the fool — that is, he is too loquacious. He and Gratiano depart, promising to meet the others at dinner.
Left alone with Antonio, Bassanio assures him that he should not worry about Gratiano's critical remarks. Antonio then changes the subject abruptly; he asks Bassanio for more information, as promised, about the certain lady to whom Bassanio has sworn "a secret pilgrimage." Bassanio does not answer Antonio directly; he begins a new subject, and he rambles on about his "plots and purposes" and about the fact that he has become so prodigal about his debts that he feels "gag'd."
