Henry VI, Part II opens with King Henry VI’s marriage to Margaret of Anjou, which was arranged as part of a peace treaty with France. The marriage proves politically disastrous, as Henry has agreed to surrender Maine and Anjou to France and provide no dowry, angering the English nobles. The Duke of Gloucester, Henry’s uncle and Lord Protector, opposes the marriage terms, while Cardinal Beaufort and the Duke of Suffolk, who arranged the marriage, work to undermine Gloucester’s influence. Queen Margaret quickly emerges as an ambitious figure who resents Gloucester’s power and begins plotting against him alongside Suffolk and other nobles.

The central conflict develops around the destruction of Gloucester, known as “Good Duke Humphrey.” Through a series of machinations involving his wife Eleanor’s involvement with conjurers and fortune-tellers, Gloucester is stripped of his position as Lord Protector. Eleanor is banished after being convicted of witchcraft, leaving Gloucester vulnerable. Margaret, Suffolk, Cardinal Beaufort, and others conspire to have Gloucester arrested on charges of treason. Before he can defend himself in trial, Gloucester is murdered in his bed, likely on Suffolk’s orders, shocking King Henry and the common people who loved Gloucester.

The aftermath of Gloucester’s murder destabilizes the realm further. Suffolk is banished by Henry after popular outcry against him, but he is captured and killed by pirates during his exile. Cardinal Beaufort dies tormented by guilt over Gloucester’s death. Meanwhile, Jack Cade leads a popular rebellion in Kent, claiming to be John Mortimer and demanding justice for the common people. Cade’s forces march on London, causing chaos and executing several nobles and officials before the rebellion is eventually suppressed. The play concludes with the return of Richard, Duke of York, from Ireland with an army, ostensibly to remove the remaining “traitors” around the king but actually to press his own claim to the throne, setting the stage for the Wars of the Roses that will dominate the final play in the trilogy.