A/N - Thank you for all the reviews, favourites and follows! And thank you in particular to GuestM, who gave me several ideas for future chapters. Let me know what you think of this chapter!

And I still don't own 'Merlin'...

-JKelly

Merlin's house was nowhere near as big as his castle in Camelot had been, but it certainly contained plenty of interesting things that he'd picked up over the centuries. Various odds and ends seemed to cover every surface, and some rooms seemed purpose built just to contain all of Merlin's many many random possessions. It was while exploring one of these rooms that Arthur came across something that confused him - well, that he recognised enough to be confused by, as opposed to the complete bewilderment that he met most of Merlin's contraptions with.

"Merlin?" He yelled to reach Merlin who had told him to 'go and explore or something' when he'd been pestering him for food - really, it was almost as though Merlin didn't think he was Arthur's manservant anymore.

"What is it Arthur, I'm busy!" Came the (frankly rude, Arthur thought) response.

"Merlin I'm confused so would you just get in here?"

An exaggerated groan came from the kitchen and there was the sound of a door opening, then footsteps down a hallway, and then Merlin walked in with an expression of complete exasperation on his face.

"Yes, Arthur?"

"What is that?" Arthur asked, pointing towards the object of his confusion.

"That? That's a globe, Arthur, a very old one so I'm not sure how accurate it is..."

"Merlin, I can see that it's spherical, but why is there a weird map printed on it?"

Merlin's eyes widened as he suddenly realised what was going on here. Arthur, the Once and Future King, the man he'd dedicated his life to waiting for and serving, the man who was supposed to be the salvation of the modern world... still thought that the Earth was flat.

"Well...oh this is going to take a while...look, come with me into the kitchen or else the food'll burn, and I'll tell you."

As Arthur settled up to the kitchen table (proximity to the kitchen was an advantage over his chambers in Camelot, he realised, where food was always served somewhat chilled) and Merlin flipped two fillets of fish onto their plates, the explanation began.

"You know all those maps you had in Camelot? How they mostly showed Camelot or the surrounding kingdoms or if it was a really big, detailed map, it might show some of the islands and land across the water?"

"Yes..."

"Well, a globe is a map that shows the whole world."

"What, even the kingdoms we weren't sure existed? How did someone even make that?" Arthur's excitement was palpable, and Merlin found himself suppressing a smirk as he remembered his obsession with finding accurate maps after his nearly disastrous trip to the Perilous Lands.

"Well, the same way they've always made maps I suppose, it's just that it became much easier to travel the world. And then of course satellite imaging came along so now you can see what it all really looks like."

"Hold on." Merlin groaned internally. This could not be good.

"If that's a map of the world, why is it on a globe?"

There was really no way of building up to it, so Merlin decided just to tell him.

"The world is round Arthur. You just didn't know about it before."

Arthur looked at Merlin for a long moment. Merlin had told him some strange things since he'd come back, but this?

"How can the Earth be round? If that was the case then wouldn't everything just...fall off?"

"Well...the thing that keeps you on the Earth, gravity, pulls to the centre of the planet, so for people in, say, Australia - that's a country on the other side of the world to us - their down is our up."

"Merlin?"

"Yes?"

"That's ridiculous. How can down possibly be up?"

"Because of gravity?"

"I always knew you were an idiot, Merlin, but I can't believe that even you would be taken in by this nonsense."

"I can show you pictures taken from space if that would make you feel better about it."

"No Merlin, there is no way that the Earth could be round. Any pictures must be faked!"

Merlin sat down heavily and sighed, the realisation hitting him.

He was looking at Arthur Pendragon - Once and Future King of Albion, greatest swordsman and strategist in the five kingdoms, and resolute Flat-Earther. Merlin couldn't help but feel that whenever this 'greatest threat' ever did rear its head, Albion would be doomed.