Donna shifted uncomfortably. "Is there anything less wooden to sit on?" she asked.

"Donna," said the Doctor patiently, "we're in a tree."

"And whose fault is that?"

He opened his mouth, saw the look in her eyes and then sighed. "Mine."

"Exactly."

They were indeed in a tree, squeezed into a child's treehouse about ten feet above the ground. They were hiding.

"It'll be dark soon," said the Doctor, "we can get back to the TARDIS then."

"When?"

"When the sun goes down."

"Which sun?" asked Donna, irritably.

The Doctor looked out of a window-shaped gap in the wall. "Well, it'll be darker when the bigger one goes away. Shouldn't be more than an hour or so." He relaxed against the wooden wall of the treehouse. "Do you want to play I-Spy?"

"No," said Donna. Then, after a pause, she added, "You shouldn't have told the Empress that we were married."

"I had to. She had that look in her eye."

"What look?"

He raised an eyebrow at her.

Donna looked at him blankly.

"Do you want to play doctors and nurses?" he asked.

She turned and pulled her hand back to slap him. "Excuse me?"

"Not you and me! Me and her! She was after my virtue!"

Donna relaxed. "Oh. Well," she said reasonably, "you didn't have to shag her, you could just have bored her to sleep with technobabble and then run off before she woke up."

"I don't do technobabble."

"Yeah, you do," said Donna. "You still shouldn't have said we were married. Couldn't you just have said you were gay?"

"I'm not."

"You're not my husband either, that didn't stop you telling everyone that you are."

"Fine," he said, "I should have thought of a better lie. Perhaps you'd like to make a list of alternatives for me to memorise for next time."

Donna nudged him with her elbow. "Don't be bitchy." She stretched her legs out as best she could in the cramped space. "I don't like people thinking we're married, that's all."

"At least she didn't just assume," said the Doctor as Donna leaned against him. He put an arm round her shoulders to keep her warm. "I don't know why people just assume we're married to each other."

Donna leaned her head on his shoulder. "It's a bit weird. Do you think we look married?"

"I don't think anyone looks married."

A thought stuck her. "Agatha Christie didn't think we were married. Because we didn't have rings on. Does that mean she thought we were living together?"

"We do live together," he said.

"Yeah, but not in sin. She probably thought we were living in sin."

"I don't see why it upsets you so much. So one of the twentieth-century's most famous authors thought that you and I were a couple, what's so bad about that?"

"Doctor, she thought we were having sex! With each other!"

"But we're not," he said. "I'm sure I'd have noticed if we were."

Donna sniffed. "I don't like people assuming."

The Doctor patted her leg. "I promise I won't tell anyone else that we're married."

"Good." She yawned. "You could have been an emperor if you'd played your cards right."

"I don't want to be an emperor. Besides, I'd have had to marry the empress and she's not my type."

Donna raised her head to stare at him. "She was gorgeous!"

"Was she?"

"Just a bit."

He shrugged. "Still not my type."

Donna went back to resting against him. "I like them tall, dark, and handsome."

"I'll keep an eye out for you," he said, generously.

Donna closed her eyes. "How long until that sun goes down?"

"Are you tired? If you want to sleep for a bit I can wake you when it's dark."

"That'd be nice," said Donna, sleepily.

She was just drifting off when the Doctor spoke. "Do you think I'm handsome?"

"How is this helping me sleep?"

"It's not, I was just wondering."

Donna moved into a more awake position. "You wonder if I think you're handsome?"

"I'm tall and I've got dark hair. That's two out of three."

"My brain doesn't go those places," she said. "I think of you as a sort of... flatmate."

"I could do worse," he said, thoughtfully. "You're clever and brave, and you're ginger as well."

"Doctor, I'm not going to marry you." She prodded him in the ribs. "And stop imagining me with no clothes on."

"I wasn't!" He looked uncomfortable. "I am now, but only because you raised the subject."

"Well, don't!"

"Don't think about pink elephants!" he countered.

Donna narrowed her eyes. "Are you calling me fat? Am I a big naked pink elephant to you, is that it?"

He moved his arm from her shoulders. "Better than being a skinny streak of alien nothing!"

"What?" She frowned. "That was months ago, are you still sulking about that?"

"I'm not sulking," he sulked, folding his arms across his chest.

"And no, you're not handsome. You're funny-looking." She tried moving away from him, but there wasn't much room in the treehouse. "Stop trying to have sexual tension with me, it won't work."

"I have more sexual tension with the rings of Saturn," said the Doctor, loosening his tie.

"What are you doing that for?" asked Donna.

"Because it's getting a bit hot in this treehouse."

Donna shook her head. "No, it isn't. It's freezing up here."

"Why are you all red then?"

"Because I'm angry!" she snapped. "I'm not the one sat here trying to get my best friend to kiss me, am I?"

"I never said anything about kissing you!"

"But you were thinking about it!"

"I most certainly was not!"

Donna reached out, grabbed the Doctor, and kissed him right on the mouth. He made an undignified squeaking sound and then kissed her back.

Finally Donna let go of him, smoothed her hair down with a hand, and said, "Now shut up or I'll do that again."

The Doctor looked dazed. "I thought you said we didn't have sexual tension?"

"Did you hear what I said?"

He nodded. "It wasn't much of a threat."

"Oh." Donna rallied. "It's getting dark out, we should get on with escaping."

"Right," said the Doctor.

Neither of them moved. Finally Donna said, "Are you just going to sit there staring at me?"

"Are you?"

Donna stood up as far as she could given the low roof. "Come on, we've got better things to do than fumbling with each other up a tree."

"I didn't fumble with you," he said, standing with even more difficulty since he was taller than her.

Donna started climbing down the ladder. "And that's the only reason you still have hands." She dropped to the ground and shook her head. "Bloody hell, you could have picked a better time for it."

The Doctor made his way down the ladder to her. "Sorry." He looked around. "I think it's that way," he said, pointing.

Donna nodded. "If you ever mention this to anyone, ever, I'll..."

"Bear in mind that kissing me isn't a very good threat."

"Shut up," she said, kindly. She took his hand and pulled him away from the tree. "We'd better get back to escaping, I don't want to die because of our sexual tension. I'd never live it down."

He nodded and together they ran away.