Just another GR refugee. Other than that, I had a stroke in 2004, and read almost anything I can get my hands on, though I have a particular weakness for history, mystery, and historical fiction.
Chapter 4: "Crises of Succession."
When we left things in Chapter 3, it was about 1325 and the French had just rolled over the English possessions in Gascony, leaving only a rump portion on the coast in English control. Edward II was in great trouble at home with his own nobles, angered by an irresolute king, his failure to emulate his father, Edward I, his unending favorites (the current ones are the hated Hugh Despensers, father and son), and his loss of most of what remained of England's possessions on the continent.
Edward's estranged wife, Isabella, has been sent to the French court to negotiate with her brother, where she has joined forces with an exiled English noble, Lord Mortimer. Now Edward II has decided that he will not do homage for Aquitaine again (he's done it 4 or 5 times now, as he has outlived 4 or 5 French kings), and has decided to send his teenaged son and heir, the future Edward III, to perform it for him.
Once Isabella has Prince Edward, she will not let him go, but will attempt to raise England against her husband, in favor of her son. And she succeeds. Edward II is pursued, imprisoned, forced to abdicate, and then mysteriously dies. Edward III, at 14, is ruled by his mother and her lover, Mortimer.
Meanwhile in France, there is a far greater succession crisis. The last of the Capet kings dies, leaving no son. His third wife is pregnant, and the country anxiously awaits the result. It is already clear that a daughter will not become France's first queen regnant (though the precedent in France is very recent, less than 20 years old, and far from a rule out of time immemorial). An infant king, however, will need a regent, and the great nobles of France, including the representatives of Edward III, meet to pick one. Their choice is Philip of Valois, the late king's closest cousin. (That he is an adult, French, and a known quantity helps - Edward is a minor himself, English, and very new on the scene.) When the baby is a girl, Philip very quickly becomes the first king of the Valois line.
Back in England, Edward III overthrows his regent, Lord Mortimer, at 17 (he leads a break-in through secret tunnels in a castle to capture him, one autumn night). And it is already clear that the tactics that worked against his father, Edward II, will not be so successful with the son, but Philip VI of France is a slow learner. (Also, according to Sumption, the worst warrior as king medieval France ever had, who was actually sane. Sumption describes him as obese, led by his fellow nobles, to whom he knew he owed his crown, and indolent, to which I'd add "addicted to pulling the cat's tail.")
It is interesting to be reading this and Ian Mortimer's The Perfect King, which is a bio of Edward III, at the same time. The major difference is that Sumption, as with many historians, believes that Edward II died in 1327 (he thinks smothered with a pillow), and that Mortimer believes Edward II did not die in 1327, and that Edward III was aware that his father lived for most of the first 15 years of his reign. (Curious as to Mortimer's argument? He's got a page on it here: http://www.ianmortimer.com/EdwardII/death.htm .)