The Fairy Queen's Bridegroom - S1.E5

The episode opens up Kelpie and a field fairy named Marigold with the 'moon'. The Earl hires Lydia (the Fairy Doctor) to work for him. The Earl holds a ball and Kelpie shows up to take Lydia back to Scotland. Kelpie wants Lydia to marry him so he stole the 'moon' from the fairy. When he tries to show Lydia the ring Paul (who is an artist Edgar likes and someone Lydia recently met) steps in and accidentally gets the ring on his finger. The Earl shows up and this ultimately ends the tussle. Kelpie returns to the water. In the end the Earl finds out his claim to the title for the Blue Knight Earl is being challenged.