Sebastian, Viola's twin brother, and Antonio, the sea captain, enter. They are strolling down a street not far from Duke Orsino's palace, and Antonio is explaining that because of his fondness and concern for Sebastian, he simply could not let him wander around Illyria alone, even though he knows that it is risky for him to accompany Sebastian. He knows that he is likely to be arrested on sight if he is recognized, but he had no choice: he likes Sebastian so much that he cannot bear to think of any harm coming to him.
Sebastian is very grateful for the risk which Antonio is taking, and Antonio tells him that it is best that already he should be taking precautions. He asks to be excused so that he can take cover. He gives Sebastian his purse, and they arrange to meet in an hour at a tavern called The Elephant. Thus Sebastian, with a purse full of money in hand, goes off to see the sights of the town.
In a comedy dealing essentially with romantic love, this scene continues to investigate another type of love — the manly love that Antonio feels for young Sebastian; he loves young Sebastian enough to follow him into the enemy's country, where he himself is in danger of being arrested and severely punished if he is discovered. But it is not merely love that Antonio feels for Sebastian; it is also jealousy, for Antonio says:
And not all love to see you, though so much
As might have drawn one to a longer voyage,
But jealousy what might befall your travel. (6-8)
The trust and affection that Antonio has for Sebastian is also seen at the end of the scene when Antonio gives his purse of money to Sebastian in case the young man wants to purchase something. This gift of money will later become an important part of the plot when Viola, dressed as Cesario, is mistaken by Antonio for Sebastian. Thus, another purpose of the scene is to bring Sebastian into the same city where Viola is, thus setting the stage for further complications involving mistaken identities. The plot is rapidly reaching the point of complication where Shakespeare will have to begin unraveling it.