The reign of England's King John is threatened by Philip of France who demands that John's nephew Arthur be placed on the throne. Pragmatic and decisive, King John moves to plactate the French, but there are others who seek disputre his authority.

Richard Duke of Gloucester, youngest brother of King Edward IV, will stop at nothing to get the crown. He first convinces the ailing King that the Duke of Clarence, his elder brother, is a threat to the lives of Edward's two young sons. Edward has him imprisoned in the Tower of London; killers in Richard's pay then drown Clarence in a barrel of wine. When news of Clarence's death reaches the King, the subsequent grief and remorse bring about his death. Richard is made Lord Protector, with power to rule England while his nephew (now King Edward V) is still a minor. Before the young king's coronation he has his two nephews conveyed to the Tower, ostensibly for their safekeeping. Richard's accomplice, the Duke of Buckingham, then declares the two boys illegitimate and offers Richard the crown, which after a show of reticence he accepts. After Richard's coronation, he and Buckingham have a falling-out over whether or not to assassinate the two children.