A violent storm rages around a small ship at sea. The master of the ship calls for his boatswain to rouse the mariners to action and prevent the ship from being run aground by the tempest. Chaos ensues. Some mariners enter, followed by a group of nobles comprised of Alonso, King of Naples, Sebastian, his brother, Antonio, Gonzalo, and others. We do not learn these men’s names in this scene, nor do we learn (as we finally do in Act II, scene i) that they have just come from Tunis, in Africa, where Alonso’s daughter, Claribel, has been married to the prince. As the Boatswain and his crew take in the topsail and the topmast, Alonso and his party are merely underfoot, and the Boatswain tells them to get below-decks. Gonzalo reminds the Boatswain that one of the passengers is of some importance, but the Boatswain is unmoved. He will do what he has to in order to save the ship, regardless of who is aboard.
The lords go belowdecks, and then, adding to the chaos of the scene, three of them—Sebastian, Antonio, and Gonzalo—enter again only four lines later. Sebastian and Antonio curse the Boatswain in his labors, masking their fear with profanity. Some mariners enter wet and crying, and only at this point does the audience learn the identity of the passengers on-board. Gonzalo orders the mariners to pray for the king and the prince. There is a strange noise—perhaps the sound of thunder, splitting wood, or roaring water—and the cry of mariners. Antonio, Sebastian, and Gonzalo, preparing to sink to a watery grave, go in search of the king.