Cassuis, Brutus, Caesar, and others are introduced during this time with the conflict of Caesar having a lot of power as king of Rome and some aren't liking this.
The conspirators must get Brutus to join in on their plan to kill Julius Caesar in order for it to go smoothly they need him. This becomes a struggle for them to get him to betray someone he's close with.
The Conspirators, Cassius, Brutus, and Casca etc. kill Julius Caesar because they think is gaining too much power for the city of Rome and don't want him to become a dictator causing. Mark Antony is allowed to speak to the people about Caesars death. During this time the people turn against Brutus and Cassius and hunt them out of Rome.
Brutus and Cassius, the main conspirators start to argue and discuss the problems at hand with their army and Mark Antony's Army. War between the two sides is being discussed and planned out for their battle.
At this time Cassius and Brutus start to realize that they will lose this war, first Cassius kills himself so the other side doesn't get the change. Brutus discovers Cassius' body and later has a servant hold his sword while he runs into it killing him.