It's a festival day in Rome. Caesar, in front of Brutus and Cassius, instructs his wife, Calpurnia, to stand in the way of Mark Antony as he runs a traditional footrace, so that he may touch her and restore her fertility, according to a Roman superstition. A soothsayer appears and warns Caesar that he must beware the 15th of March. Caesar dismisses him and leaves Brutus and Cassius alone.
Cassius asks Brutus why he has been unfriendly lately, and Brutus tells Cassius he has been preoccupied. Overhearing the crowd, Brutus worries that the Roman people may be trying to crown Caesar king. Cassius, seeing Brutus’ discomfort, explains that he thinks it is unjust for an ordinary Roman to be valued above all the others. Cassius believes Brutus is as great as Caesar. Brutus agrees that things have become unpleasant in Rome. Meanwhile, Caesar passes by, returning from addressing the crowd, and confides in Mark Antony that he does not trust Cassius.
Brutus and Cassius catch their friend Casca as he is returning and he bluntly tells them what happened: Caesar refused an offered crown three times, and swooned in public. Cassius invites Casca to have dinner with him. When he leaves, Cassius and Brutus agree to meet the next day to speak about the situation in Rome. When Brutus leaves, Cassius explains that he is trying to win Brutus to his side for some endeavour, since Caesar distrusts Cassius, but loves Brutus.
Interview: Caesar, Calpurnia, and Antony