King Arthur! is a magazine story.
The Fat Controller chooses Arthur to deliver costumes to the castle for the special medieval open day. Emily is taking passengers to the castle and together Arthur and Emily watch the fun.
That night, Arthur dreams that the shed is a castle. Next morning, he tells his dream to Emily who has an idea which she tells to the Fat Controller.
A week later, something special arrives from the works for Arthur - a cardboard crown! Meanwhile, a truck cover is draped over Emily's boiler and it looks just like a fine cloak. After the other engines have finished work, they all lined up in the yard where Lady Hatt has made lots of refreshments. The Fat Controller then reads out an old story about engines, and Emily calls it "King Arthur and his Engines of the Turntable". Arthur then rotates slowly on the turntable so that everyone can admire his magnificent crown.
- In the 2011 version, an exclamation mark was added to the title.
- This story is a reference to the legends and literature based on King Arthur.