User blog comment:Ḡwẵine Ḹٍٍkƨ Ĺiĸe Ͼềлȑềd/Arthur's Reaction After Learning Merlin's Magic/@comment-4814726-20120421163751

When arthur learns Merlin has magic, he will attack him like he did Lancelot, but then stop because merlin was such a friend to him that he cant kill him. I think he will do the same thing with Guinevere and banish him "under pain of death". If there is another ep after this, it will see Merlin living with the Druids, and Arthur trying to hun him down.

OR: Arthur will sentence Merlin to death after finding out in his chambers. Merlin I think will grab a dagger and put it to his own throat, saying that he had promised to serve Arthur until the day he died. Eventually, (after hopefully some tears) Arthur orders Merlin to put the dagger down, and he says he is not going to execute him.

From here I have a vague plan of the ep but that goes beyond the blog post.

So, thats what I think will happen.