Eames is a were-unicorn, and Arthur is the architect unknowingly out to destroy Eames' home. The rest is just a fairytale love story.

"The king sent me to get you," Merlin said, with a tone that implied strongly that he wasn't rolling his eyes where Arthur could see, but just wait until his back was turned. "He said you're to get changed into formal clothes and meet him in the Great Hall, there's a delegation coming from the Summer Court."