How do the interactions between major and minor characters in act 4 develop the plot of the tragedy of julius caesar? the audience learns about the assassination plot against caesar and the role each major character will play in the assassination. the audience learns about the soothsayer’s prophecy and calpurnia’s dream, both of which are meant to protect caesar from the assassination plot. the audience learns about the effects of mark antony’s and brutus’ funeral speeches and the effects they had on the people. the audience learns about the trouble within the second triumvirate, the breakdown of brutus and cassius’ friendship, and octavius’ troops being strong and ready to fight brutus’ army.