Hi :)
I happened to see your question on the ONC message board and thought I might help. I have already submitted my story for the second round and here's what I wrote in that last section of the form:
'I'm using prompts #4 and #52 to retell the Arthurian legend. Princess Guinevere ( in disguise) becomes a temporary bodyguard of Prince Arthur who comes to her father's realm for a week long trip-- to try to pull the sword from the stone and thus become the once and future king.'
If you look at the blurb of my story-- A week with a prince-- it might make more sense :)
Now, I can't know if this is the correct way to do this, but still, hope this helps. Good luck in the next round.