King John Synopsis
Scene: England and France at the beginning of the thirteenth century

Chatillon, an ambassador from King Philip of France, demands King John’s crown for Arthur, young son of John’s dead elder brother, Geoffrey, whereupon John declares war. He is followed to France by Philip the Bastard, who has been created Sir Richard Plantagenet on the revelation that he is the illegitimate son of King Richard I.
Before Angiers (200 miles SW of Paris) the English and French armies meet (Act II). When the citizens declare that they will recognize only the rightful King of England (“he that proves the King,” / To him will we prove loyal”), the two armies temporarily unite to assault the town. Peace of a sort is made after the citizens have suggested that Lewis, Dauphin of France, should marry John’s niece, Blanch of Spain; Arthur is to become Duke of Bretagne (Brittany).
Constance, the boy’s mother, assails King Philip and his ally, the Duke of Austria (Act III) for his treacherous bargain. The new-patched peace is brief; Cardinal Pandulph, the papal legate, arrives to excommunicate John for disobedience to the Pope; and because King Philip is also to be excommunicated unless he breaks his pact with John, the battle begins afresh. The Bastard kills the Duke of Austria; Arthur is taken prisoner and sent to England, Constance mourning for him; and John secretly orders Hubert de Burgh to dispose of the boy.
Hubert (Act IV), receiving a royal command to blind Arthur, resolves instead to hide the boy and to announce his death, false news that takes from John the support of Lords Salisbury and Pembroke. All troubles press on him at once: the Dauphin is ready to invade England; John learns that his mother, Elinor, has died – so, too, has Constance – and now the barons fall away from him. Though he learns from Hubert that Arthur is alive, the boy has actually been killed in an attempt to escape from Northampton Castle.
John yields to the Pope (Act V), but the Dauphin refuses to obey Pandulph’s order to return to France, and supported by the English barons, fight with John’s army. Retiring to Swinstead Abbey in Lincolnshire, the King is joined again by Salisbury and Pembroke who have heard that the Dauphin intended to kill them. At Swinstead, John – poisoned, it is believed by a monk – dies in the orchard; Lewis by then has withdrawn his army, leaving Pandulph to arrange terms for peace, and the Bastard acknowledges the young Prince Henry as Henry III.
-from The Pocket Companion to Shakespeare’s Plays by J.C. Trewin