Merlin - The Changeling

Arthur is to be betrothed, to a woman he doesn't love.  It's Princess Elena but unknowingly, she bears the spirit of the pixies who invaded her body when she was a baby.  They have been waiting for this day so that they can take over the throne of Camelot.  Of course, Merlin sees that the Princess' Nanny is not who she seems (a familiar plot point in this series).  Will he be able to stop the wedding without revealing his powers?
I love the Princess as a character though!  She was so un-ladylike and hilarious!  And the Pixies are bastards!
A fun episode but these storylines are getting a bit over used.