A Bloody Field by Shrewsbury

It is 1399 and Henry has returned from Ireland because Richard II has been incarcerated in The Tower.  Henry's father is crowned king of England and Henry becomes the Prince of Wales.  Henry's guardian and tutor is the legendary Sir Henry Percy, also known as Hotspur.  Not long after this, Richard dies.

Wales is in rebellion and Hotspur wants to settle the dispute without further war.  He begins secret negotiations with Owen ap Griffith, leader of the Welsh.  At this time, Lord Grey takes it upon himself to make an incursion into Wales.   Unfortunately for him, Griffith kills his men and takes him hostage.  Meantime to the north, the Scots are causing trouble.  Hotspur must head north, leaving the young prince in charge of the marches.

Not long after this, Edmund Mortimer is taken prisoner after a battle with the Welsh.  King Henry decides he has no choice but to go to war with the Welsh.  Unfortunately for him, he is rebuffed, not in battle, but by a viscous autumn storm.  Defeated and humiliated Henry returns to England.  To the north, Hotspur has better luck, defeating the Scots and taking Lord Douglas captive.

Desperately in need of money, King Henry orders all prisoners held for ransom to be turned over to him.  Hotspur does not like this order.  Henry's demands will turn his foremost supporter against him.  What ensues sets the future for the War of the Roses.

Author Edith Pargeter has written a very good historical novel that outlines the House of Lancaster's claim to the throne of England and how it was secured in a single battle.  A good read.