The battle lines are drawn in this first scene, taken up right from the conclusion of 1 Henry IV. At the end of the prior play, Suffolk woos Margaret for the king because he could not have her (being already married), and he delights at the powerful influence he will have over Margaret and, thus, over the king. 1 Henry IV laid the groundwork for disagreements between Gloucester and Beaufort (then called the Duke of Winchester), who argued because Gloucester was the protector of the kingdom and Beaufort the head of the church. Struggles boil between Somerset and York, who respectively selected the red and white roses as symbols of the side they and their men take against each other. The excuse for Somerset and York's argument came first from a disagreement about a point of law and later from Somerset's slowness to provide York with reinforcements in the French wars, causing the death of England's greatest warrior.
The struggle between Somerset and York will become the War of the Roses, fought between Lancasters and Yorks with the professed intent of returning the house of York to the throne. York believes that King Richard II was illegally removed from the throne by Henry IV, the present king's grandfather. York believes he should hold the throne, as the eldest link to the eldest of Richard II's brothers still living after Richard's fall. His ambition to one day gain the throne motivates his every action.
Yet first the disagreement between Gloucester and Beaufort must be dealt with. Beaufort has always wanted to oust Gloucester; to accuse him of plotting to gain the throne is the latest in a string of schemes against Gloucester. Yet Gloucester is popular with the people; in a world where all the nobles are rotten, their support defines Gloucester as authentically honorable.
Henry's inattention about the articles of the peace treaty is an early sign of his weakness as a king. All his lords agree that lands so hard won in France should be kept, but Henry doesn't care. Yet none of his lords are prepared to advise him, including the Protector, Gloucester. It is as if they have already given up on Henry and can only see misfortune in the future--as Gloucester predicts when he departs the scene. Now all that remains for the lords is to jockey for the best possible position during the apparently inevitable fall of a weak king.
Margaret is also not so meek as she first appears. She fully intends to take advantage of her position and the weakness of Henry, both to control the realm and to have an affair with Suffolk.