'Lady Catrina, is it really you?' Uther watched the woman walking into the council chambers in disbelief.

Thalia watched patiently as the Lady Catrina walked to the king.

'I can hardly believe it myself.'

'We had tidings from the north that the House of Tregor had fallen to invaders.'

'All that you heard was true, My Lord, and worse.'

'Your father, the King?'

'Gone, Sire. The enemy attacked without warning. We were outnumbered five to one. He could not endure. I would never have survived had it not been for my faithful servant Jonas. But we did survive, and we have made it this far...'

Catrina swooned and Thalia started, meaning to help, but Uther caught her.

'Forgive me, My Lord. I fear my trials have taken a toll.' Catrina looked up at him.

'Your sufferings are beyond imagining, My Lady. It would be an honour to help you in any way we can.'

'A bed for the night would be most welcome.'

'And consider yourselves our esteemed guests. It's the least we can do.'

'Thank you.'

They left the chambers once more.

In the evening Arthur and Thalia bumped into each other on their way to dinner. 'Is Catrina settling in?'

'Mm, I had Merlin make sure she has comfortable chambers.'

'Mmm…'

'What?'

'Hm?'

'You're zoning out again.' Arthur had a smile on his face.

'Oh am I? Sorry.'

'Come on, let's go to dinner.'

'Well, this is wonderful. Thank you.' Catrina smiled at them all.

Thalia sat beside Arthur and opposite Morgana.

Uther spoke over the maid's arm as she poured wine into his goblet. 'It's an honour. The Houses of Tregor and Pendragon have been allies for as...well, as long as anyone can remember.'

'My father often spoke of you, My Lord.'

'And I will remember him always.'

'I'm sorry I didn't get the chance to meet him,' Arthur said.

'As am I,' spoke Thalia.

'I'm sorry too. For the House of Tregor is no more.' Catrina pushed her food away.

'Well, no, Catrina, it lives on in you.' Uther spoke gently.

'I only wish that were true.'

'It is, My Lady. Your courage, your modesty. And you are as you always were, ever since you were a child.'

Thalia glanced at Arthur's confused and unimpressed face and exchanged amused looks with Morgana.

'Ah, I fear I am much changed since then, My Lord.'

'Oh, yes, it's true. You are far more beautiful now.'

Morgana and Thalia looked away, smiling while Arthur's face became even more of a frown. He faked a yawn.

'I'm sorry, hard day's training. If you'll excuse me.'

'I'll take my leave as well, I think, like Arthur said; hard day's training.'

'Of course,' Catrina smiled.

'Arthur. Thalia.' Uther nodded at them as they left.

The moment they were out of the room and earshot Arthur scoffed.

'Arthur!'

'Well really, it's suffocating, look at him, he's like a lovesick puppy!'

'As opposed to you?'

'Yes!'

'Arthur, you're a dim-witted prat, at least your father's a romantic!'

Another scoff. 'And I'm not?'

'Not as "lovesick puppy" as he is, no.'

'Oh! If you say so.' Arthur put an arm behind her waist and pulled her in, kissing her.

'How did I know you'd turn that into flirting?'

'I don't know,' he said, 'perhaps you were, too?'

'Is this conversation going anywhere?'

'Mmmm… not that I can see.'

'So we're just going round in circles.'

'Seems like it.'

The next day Arthur, Merlin and Thalia were in the main square grooming horses when Uther and Catrina rode in. Uther helped her down from her horse and both he and Catrina giggled.

Arthur turned his nose up. 'Honestly. Look at them.'

'Don't you think it's odd how quickly they've become close?'

Thalia glanced at Merlin, knowing he was insinuating something. Arthur, on the other hand and predictably, didn't notice.

'There's nothing odd about that. My father's a wealthy and powerful man.'

Thalia gestured Merlin round to the other side of the horse.

'Well?'

'Gaius was first suspicious. He said the Lady Catrina suffered from an illness that made it hard for her to walk and her bed wasn't slept in last night. Oh, and her chambers stink and her servant, Jonas, has a tail.'

Thalia frowned and quickly double checked. 'A what?'

'A tail.'

'… right. Let's have a look tonight. Her chambers are just below Arthur's aren't they?'

'Good thought.'

At night after Arthur was asleep Merlin and Thalia crept in like they were out in the woods hunting. Merlin took the round mirror from beside his bed as Thalia quietly opened the window. At the sound of the latch Arthur stirred but only rolled in his sleep.

'Scéawere, folge min bebod.' Merlin's eyes glowed gold and the mirror floated down.

'Angle it up more. Yes, good.'

'I can't see anything.'

'Wait… wait…'

Thalia and Merlin both recoiled slightly in shock. There, in Lady Catrina's dress, was a troll.

'Merlin.'

Thalia and Merlin jumped and span round at the sound of Arthur's voice. The mirror crashed to the ground below them and they winced.

'I have no doubt, Merlin, that you have prepared a very good explanation for this.'

'Yes. No. Er...'

'Apparently I'm wrong.'

'Well we do,' began Thalia, 'it is the truth but you'd never believe it.'

Arthur rolled his eyes and shoved Merlin out of the way, to look out of the window. He came round.

'Please tell me you weren't spying on Lady Catrina.'

Merlin stuttered. 'It's not what it seems.'

'Well, technically…,' Thalia began.

Arthur ignored her. 'Yes, Merlin. It's exactly what it seems. You have led a sheltered life, you have no social skills whatsoever, and Catrina is, I admit, an attractive woman. I understand completely.' Arthur was trying not to laugh. 'And if I ever find you doing it again, I'll feed you to the dogs. Do I make myself clear?'

'Yes, absolutely, Sire.' Merlin ran out. Thalia stepped in front of Arthur.

'Like I said, plausible explanation, but you wouldn't believe it.' She patted his head, causing his sluggish blue eyes to flash with utter bewilderment. 'Goodnight.'

Merlin was waiting outside.

'Looks like I'll be reading up on trolls, then.'

'This can't be happening.'

They followed the troll to underneath the castle. When they got around a corner they saw the troll lying happily amongst leaves and food waste. They exchanged disgusted looks and backed out slowly, heading back into the castle.

'You tell Gaius, I'll go read.'

'Ah, Merlin. What does Gaius say?'

'That we're beyond the point of return. He's gone to tell Uther the Lady Catrina is a troll.'

'Oh did you wish him good luck?'

'Yes.'

'Good. How much?'

'A lot.'

'Even better.'

The next morning Merlin knocked on Thalia's door.

'Merlin.'

'How did you know it was-'

'No one knocks like you. It's the same method I know it's Arthur, and my maid, and-'

'You have a maid?'

Thalia opened the door. 'Yes, I gave her a few months off a while back; her father's sick.

'Ah I see.'

'Well? Uther?'

'Gaius spoke to him, nothing.'

'As expected. Uther's a bit of a nightmare.'

'Any ideas?'

'Well if you can turn her back into a troll when she's visible to the entire council it might work.'

'How do I do that?'

'The closest I've come is the spell of revelation. Take one of my books and keep looking to be sure.'

'I will, thank you.'

A knock sounded at the door.

'Yes?'

'My lady, the king demands your presence in the council chambers.'

'Oh fantastic.'

Thalia went out of her chambers to see Arthur walking the same way.

'I think my father's going mad.'

'I think you might be right.'

Uther and the Lady Catrina walked to the front, Uther looking as dazed as ever. 'Thank you all for coming. You are, no doubt, wondering why I have gathered you here today. Though we live in dark times, today I bring you light, and love.' While Uther looked at Catrina Arthur and Thalia exchanged a look. Uther was behaving beyond strange. 'It gives me greatest pleasure to inform you that the Houses of Tregor and Pendragon are to be united in the closest bond of all. I am to marry Lady Catrina of Tregor.'

Thalia felt Arthur's arm brush against hers as he squirmed uncomfortably, looking in shock at everyone else who was clapping. Catrina whispered something into Uther's ear and the king spoke once more.

'I am to marry Lady Catrina tomorrow!'

Slower claps rang out.

'This union heralds a new dawn for the kingdom, a new beginning...'

Catrina's smiling face dropped suddenly and she stared ahead as Uther kept talking.

'...and a new queen for all here in Camelot. I could not hope to have made a better match. I hope you will all share in our joy.'

The council applauded.

'Thank you.'

Thalia glanced at Merlin who shook his head hopelessly.

Thalia and Merlin approached Arthur slowly in his chambers. He noticed them.

Merlin opened his mouth a couple of times.

'Yes?' he slid his sword into its sheathe.

'Arthur. We're going to tell you something... … It's not going to be easy.'

Thalia and Merlin shook their heads.

'…Right.'

'It concerns the Lady Catrina.'

'You're not using my chambers to spy on her again.'

'We had a valid reason!' Thalia groaned.

'Arthur.' Merlin took a breath. 'She's a troll.'

Arthur laughed heartily and turned to them. 'She's not that bad.'

'I'm serious. She is. She's an actual troll.'

'Merlin, I know what you're trying to do, and I appreciate it. You're a true friend. But it's not about whether I like her or not, it's about what makes my father happy. And when they announced the wedding today, I realised that Lady Catrina does just that. She makes him happy.'

'Well, he won't be so damn happy when he discovers his wife's a fruit munching monster.'

'That's enough, Merlin.'

'But…'

'She's the future queen of Camelot whether you like it or not. So you better get used to it.'

'… Arthur, do you think we just get bored and so decide to come and tell you that your future stepmother is a troll? We're actually warning you.'

'Thalia, stay off the cider. Ow!' Arthur rubbed his shoulder and watched as Thalia dragged Merlin out.

'I need to go train the Knights, Merlin, I'll see you later.'

Thalia stood on Uther's left side, Arthur on his right. She hadn't heard from Merlin and was starting to get worried but there was nothing she could do to stop the wedding, being the Crowned Warrior and the Prince both she and Arthur knew the chaos it would cause should any of them express open objection to the king's wedding.

They walked to the front and Arthur and Thalia stayed at the front of the crowds while Uther went up onto a step.

Catrina soon entered amongst a fanfare and walked to the front. She and Uther held each other's hands.

Geoffrey, the man who resided in the library and records most days, began the ceremony.

'My lords, ladies, and gentlemen of Camelot, we are gathered here today to celebrate, by the ancient right of handfasting, the union of Uther Pendragon and Lady Catrina of Tregor. Is it your wish, Uther, to become one with this woman?'

'It is.'

Thalia didn't let herself squirm. She didn't know where Merlin was.

'Is it your wish, Catrina, to become one with this man?'

'It is.'

'Do any say nay?'

Arthur glanced at Thalia who looked like she was biting her tongue to keep herself from speaking.

Geoffrey produced a garland. 'With this garland, I do tie a knot, and by doing so, bind your hands and your hearts for all eternity.'

Suddenly, Thalia fought hard to not laugh. Uther, bound to a troll for all eternity. She could imagine his face when his senses returned.

'I, Uther Pendragon, King of Camelot, I shall not seek to change thee in any way. I shall respect thee as I respect myself.'

Thalia fought harder, biting her cheek and clenching her jaw.

Catrina spoke her vows and Geoffery spoke once more.

'I now pronounce you to be husband and wife.'

They kissed and Thalia applauded with the rest of the court. She turned and saw Merlin standing in the doorway, dirty and panting.