Ok, I have 10 minutes, and here I go.
So, Arthur and Merlin come out of the forest, with Cully the Hawk, and are spotted by Kay and the King. Arthur explains about Merlin, sorry, Merlyn. Kay does not believe about Merlyn being a magician, and Merlyn promptly says “Tree”.
Then, a thing so amazing you probably guessed it before I tell you happens. Can you guess? A tree grows out of nowhere. Kinda obvious, with the whole magic thing. Kay still doubts him. So, Merlyn says “Snow” and “Umbrella”. Guess what happens? A giant evil snowman with a magic umbrella appears
It starts snowing, and everyone gets freezing, except for Merlyn, who has an umbrella (what a surprise). Sir Kay still doubts this one-word-sentence magic man, and Merlyn gives up trying to persuade him. They all go inside to get away from the summer snow.