The play opens to a funny setting with a little word play between Flavius, Marullus, and a few workers. The workers are on their way to see Julius Caesar who has recently returned from his battle against Pompey. As Caesar talks to Mark Antony, we learn that Caesar is superstitious. To keep with the idea of the supernatural, a soothsayer speaks, warning Caesar to beware the Ides of March. He acts as like he is not concerned. After the talking with the soothsayer, Caesar is offered the crown three times and refuses each time. At the same time, Cassius is trying to convince Brutus that Caesar is too powerful and should be killed before being allowed to rule the Roman Empire. Brutus says that he will not betray his honor and loyalty to Rome. That evening the weather is very strange and violent. Most of the people believe that the weather is a bad omen, but Cassius disagrees. He uses the unusual weather to reason that it is only for evil men who need to be afraid.
Brutus is convinced by Cassius that it is for the good of Rome that Caesar be killed. Some of the other conspirators want to kill friends of Caesar's, but Brutus feels that that no one else needs to be killed. The person responsible for the downfall of Rome should be the only one to be killed. While this is happening, Caesar is thinking on whether he should stay home during the Ides of March. Calphurinia, Caesar's wife, tells Caesar of the horrible dream she had about his death and that the strange occurrences the night before are a warning of his death. He agrees to stay until Decius, a conspirator, tells him her dreams were not of his death, but of him saving Rome. This makes Caesar leave for the Senate despite his wife's wishes. Artemidorus waits in the streets of Rome for Caesar to go by so he can give him a note, warning Caesar of the conspiracy.
Many attempts are made to warn Caesar of the plot to kill him, but none are successful. Caesar is murdered...