Author's Note; It has been so, so long since I've done this that I've practically forgotten how to. I'm putting this as a T, as it isn't strongly adult enough to go up to an 'M' in my view. First things first;

1) I am not an Arthur/Gwen shipper. End of.

2) I do not own Merlin, its characters or anyone. I own only the plot and my own characters.

After sharing a final night together, they go their separate ways. But there's one small thing she's forgotten to tell him about. His son - the secret heir to Camelot's throne

It all started after the dragon left Camelot. Everyone was celebrating; there were bonfires being lit, people getting drunk after barrels of wine were rolled out and endless music streaming from the castle. Merlin had already staggered away, filled with a sense of pride and accomplishment, that even though Arthur had been given all the credit, he knew they were all celebrating because of him. Everyone was having a good time, enjoying themselves for the first time in what seemed like forever.

She stood there in the same place she'd been when she first saw noticed him coming back - battered and bleeding - before throwing herself into his arms. The relief she felt had been so substantial she didn't feel she'd be able to convey it all in one action. She could remember the agony of waiting, perched on a stool and twisting a cloth between her hands, for hours. Waiting for any sign that something was happening, someone was returning. And now here he was, safe and sound, and it was the best she could do to not cry with relief.

The light from the nearby bonfires flicked against his face, dancing in his eyes, and she slowly lifted a hand to touch the developing bruise under his eye. At her touch he flinched and she automatically withdrew her hand until he gently pulled it back. For a moment they stood there, in silence, relishing in each other's presence. And then, she could no longer stand it.

Someway, somehow, she found herself in own home, tripping over her own wooden stool, him staggering behind her. He crushed her to him and she grabbed a handful of his chainmail, cursing it for not being an easy material to hold. Before she knew what was happening, he was kissing her and she - stupid fool - was kissing him back, hands lost in his thick hair. They staggered about the small room, bashing into various furniture, in an unrehearsed dance, but all she could think about was that this was the moment she'd been waiting for. It just wasn't going how she'd visualised. For a moment she was released as he pulled off any clothes he could and she took the moment to kick off her own shoes before grabbing him once more in a tight hold.
Tripping over their own discarded clothes, they fell heavily onto the bed and she realised for the first time how heavy chainmail really was. With his hands in her hair and his voice muttering sweet nothings into her ear, she held him close as if he were liable to drift away as easily as the night. As she lay there, feeling his breath fall hot and heavy onto her neck, she noticed the developing hole in the roof and wondered just how long it had been there before he found her mouth again and the roof was forgotten. And then finally, finally, the moment she'd dreamt of for so long. With her hands entwined around his neck, head thrown back, they finally came together and it was this moment - this specific moment - that she realised this was the beginning of the end.

With a groan, Prince Arthur let his head fall, thudding against his own chainmail covered arms.

"Why, Father? I'm perfectly fine as I am!"

"Because." King Uther started, raising one hand from the table to make his point. "You are the crown prince, meaning you will be king. And as king, you need heirs. For heirs, you need a wife. It's as simple as that."

"Yes, but why now?" Arthur protested, glancing up. "And why can't I choose my own wife?"

"You can." Uther said, tapping his finger against the arm of his throne. "But from a selection of my choice. Arthur, you're 21 - the sooner you're married and producing heirs, the better it is for Camelot. Look how many times your life has been threatened. You're going to need to have a good few sons to keep the throne safe and without a wife, you'll get nowhere. Better to start while you're younger."

"Yes, fair enough, but can't I at least pick who she is? A lady of Camelot would be a good idea, one of our own..." He said wistfully, thinking of a girl who was no doubt collecting water somewhere in the castle.

"Absolutely not." Uther said, snapping Arthur out of his imagination. "It is in the best interests of Camelot that you marry a neighbouring princess. That way we can secure two kingdoms together and create an alliance. I hear King Stefan has a beautiful daughter. Princess Bella. Infact, I have invited them to Camelot."

"You've WHAT? Father!" Arthur cried, shooting up in his seat. Uther frowned but Arthur stayed straight, a horrified look plastered to his face.

"In a week. I fully expect you to receive them and, for goodness' sake Arthur, consider Bella. She has many suitors for her hand and I hear she is a most delightful young lady. We will speak no more of this." Uther said and with a wave of his hand, the guards opened the doors. Arthur didn't need a dismissal. He was out of his seat and striding off before Uther had finished his sentence.

It had been four months. Four months, two weeks and half a day and Gwen could still remember it as vividly as yesterday. And yet...to remember also hurt her. For since that night, Arthur had not looked her in the eye once. She'd tried to tell herself it was because he was dying over not being able to be with her too but secretly, she felt it was because he was ashamed. Maybe it was easier for him just to forget it even happened.

For Gwen, this was not even possible.

She'd figured it out after two months and now she was positive of it. She had told no one - had no intention of telling anyone - and had no idea what she was going to do when it became obvious. In her heart of hearts, she knew it would be the right thing to tell Arthur. But what good would that do other than open up a a new can of worms for him? As she arranged another vase of flowers in the absent Morgana's room, she sighed sadly. Out the window, she could see Arthur. He was striding across the courtyard in the direction of Merlin and - to be frank - he looked furious. She watched as he grabbed Merlin from his work and tell him whatever it was that had happened before turning away. Watching him go so easily about his life only made hers harder.

Not as hard as what he'd left her with though