Caliban plots to kill Prospero, his master, with Stephano and Trinculo. In act 3, scene 2, Caliban gets drunk with the two shipwreck survivors and boasts about his knowledge of Prospero's habits, claiming to know how he can be killed.

Then, Stephano and Caliban engage in a kind of drunken plot to kill Prospero and make Stephano "king" of the island. He tells Stephano that he will take him to where Prospero sleeps and that he should kill him in his sleep after first taking his books, which are the source of his magical power. Caliban also tries to tempt him by describing the beauty of Miranda. Stephano decides that he will kill Prospero and take Miranda for his queen, and Caliban and Trinculo will become nobility.

Of course, Ariel has been witness to all this and warns Prospero of the plot. Ariel, who has made himself invisible, plays a tune on his pipe that enchants the three and leads them off into the wood, where he causes them to wade into a disgusting pond. In act 4, Prospero gets Ariel to trick Caliban and Stephano by distracting them with fancy clothes, which they steal. Prospero conjures dogs who chase Caliban and Stephano away.