Here are some one liners...
China's Great Wall and the Lost Emperor -- After a successful battle with the Mongols the Chinese Emperor is captured on his way home by a force of 5,000 Mongols. How does a force of 5,000 beat a force of 500,000? Carefully.
Say Hello to My Little Friend: Mons(ter) Meg -- Mons Meg is a bombard cannon that throw a quarter ton projectile. It is a gift by the Duke of Burgundy to King James the 2nd of Scotland.
The English Get Spanked By the French... Again -- King Henry the 6th of England is losing battles and land. He is going to lose France entirely and this will set up the conditions for the War of the Roses.