In the midst of a storm, Casca and Cicero remark upon the strange, almost supernatural occurrences Casca has seen lately. Cicero leaves, and Casca meets Cassius, who is fired up about the threat Caesar’s rise poses. Casca tells Cassius that a group of senators plan to make Caesar king the next day, and Cassius vows to commit suicide before becoming a subject of Caesar’s. He tells Casca that he’s already recruited some of the noblest Romans to undertake "an enterprise."

Cinna, who is in on this “enterprise,” approaches. After he expresses his hope that Cassius can win Brutus over, Cassius hatches a plan. He gives Cinna some letters advocating for their cause to distribute where Brutus will find them. Then they’ll gather with the other conspirators at Pompey’s porch. After Cinna departs, Cassius and Casca decide to pay a visit to Brutus’ house, where they’ll try to convince him to join their cause.