Amy Pond threw back her head and laughed, the half-mask covering her eyes slipping a little farther down her face at the sudden movement. "Only you, Doctor," she said. "Only you."

The Doctor shot her an affronted look. "Are you trying to tell me there's something wrong with my costume, Pond?"

"Don't be ridiculous," Amy said, reaching up to push her mask back up her nose. "I'm saying that everything is wrong about your costume."

Blinking in surprise, the Doctor made a few sputtering sounds before he managed a strangled-sounding, "What?"

Amy moved her gaze over him, trying to stifle her laughter. In his purple robes and gaudy pointed hat, the Doctor looked like a wizard straight out of those cheesy cartoons she had watched as a child. Or, at least, like a wizard's apprentice dressing up in his master's clothes. "I don't think you look quite old enough to pull off a Merlin costume, Doctor."

He frowned and looked down at his robes. "That's ridiculous. I am Merlin."

She stared at him. "Seriously?"

"Well, I will be Merlin," the Doctor said. "Or, at least, I was supposed to be Merlin. Though there's a possibility that the Time War changed things." He paused, tilting his head a bit. "Maybe I should look up Bambera, see if Ancelyn is still part of the timeline."

Amy's mouth twitched as she folded her arms in front of her. "You're trying to change the subject."

"Trying to change what subject?" the Doctor asked, turning his attention back toward her.

Amy rolled her eyes, smiling despite herself as she turned away from him and walked over to the railing at the edge of the ship's deck. The water was calm, and in the distance she could see the lights of the nearby city where they had left the TARDIS. On the other side of the ship, where the costume party was going on in full swing, she could hear people talking and laughing. They really should be getting back; the royal family was probably wondering where she and the Doctor had gone.

In the sky, stars were spread out above them in patterns that she'd never seen, mixing around the triple moons that were lighting up the night sky almost as bright as daylight back on Earth. Maybe it wouldn't hurt to stay over here, in the quiet, for just another few minutes.

Amy gasped when the Doctor suddenly rested his hand on her shoulder. She hadn't even heard him coming up behind her.

"Amy?" he asked softly, a hint of worry in his voice.

"Sorry," Amy said, not quite meeting his gaze. "I was just thinking."

The Doctor shook his head. "There's nothing wrong with thinking." He paused. "Well, there is, but I doubt you're thinking about ways to take over the known universe, so it should be safe."

She laughed, reaching over to lightly punch his arm. "I'm taking a break from plotting universe domination for the night."

"Good, good." The Doctor nodded. "I suppose that means I don't have to try to think of ways to stop you."

Amy shook her head, her gaze drifting back up to the stars. A few seconds later, the Doctor leaned against the rail beside her, following her gaze with his own.

"What do you see?" he asked.

She didn't look at him. "It's stupid."

"The most important things usually are," the Doctor replied. Amy glanced at him, raising an eyebrow.

He smiled. "Well?" he prompted gently. "Are you going to tell me what you see? It can't be any worse than some of the ideas for constellations that ancient humans came up with."

Amy snorted. Then she reached up with one arm, pointing at a group of tightly clustered stars. "Those," she said quietly. "For some reason, they remind me of a healer of some sort." She blushed. "I told you it was stupid."

"A healer?" the Doctor repeated. He reached over and flicked her ear, smiling gently. "You mean like a doctor?"

Amy laughed, ducking her head a bit. Then she paused. "Yeah, I suppose. Like a doctor. Or-"

The Doctor's smile faded a little. "Or?" he prompted gently.

She shot him a sheepish look. "For some reason, it reminded me more of a nurse. I don't know why." Amy frowned, not sure why she suddenly felt as if she was forgetting something important. "I mean, I don't even know any nurses. I haven't known any since I was a kid, when my aunt finally stopped sending me to visit psychiatrists."

For a moment, neither of them said anything. The smile on the Doctor's face completely disappeared as he stared up at the stars.

"I traveled with a nurse once," the Doctor said softly, "or, more accurately, he traveled with me. He was a good friend."

Amy tilted her head. "What was his name?"

"Hmm?" the Doctor asked.

"This nurse friend of yours," Amy said, rolling her eyes. "What was his name?"

The Doctor hesitated. It only lasted a moment, short enough that Amy thought maybe she was just imagining it. "Hex," he said. "Hex Schofield. Brave man, Hex. Willing to do anything to protect the people he cared about."

Amy smiled, her gaze drawn back up to the stars. "That's nice."

The Doctor reached over and rested his hand on her arm, drawing her gaze back toward him. He stared at her a moment, like he was about to say something, then he shook his head and pointed up at the constellation that had caught her attention.

"The locals call it kri'lopsa," he said softly. "They used it to navigate centuries ago. It's one of the most important constellations to them."

Amy looked back up, staring up at the stars for another few seconds. Then she sighed. "We should probably get back to the party. I'm sure the queens are wondering where we've gone."

The Doctor nodded. "Lead the way, Pond," he said, offering her his arm.

Amy glanced upward one more time. Then she sighed, shook her head, and hooked her arm in the Doctor's. "Come on, back to the party."