"River." The Doctor pondered the word. Had he meant it as a question, a statement, a demand, an order? He wasn't certain. But he said it again. "River."

River's thick mane of curls bounced as she glanced up at him from the console. With his eyes, the Doctor traced the lines carved into her face. She was aging, though she tried to hide this inevitable fact of her biology from him. Sometimes the Doctor wondered if she had forgotten – he could sense time passing, and he knew hers was slowly racing away from her.

Mistaking his words and facial expression for a certain question, River returned to fiddling with the controls. "He's asleep," she said.

The Doctor knew this, but he instead said, "Can't blame him." He studied his long, thin fingers. They were blue, reflecting the calming glow of the TARDIS. Oh, his good old blue box. He smiled.

River's chin dipped in agreement. The glance she shot his way told him she knew there must be more. The Doctor hurried to the point. "I saw you tucking him in."

For a moment, River froze. Her arms were perched, painfully straight, on the rim of the console. She stared at the Doctor, her eyes flecked with guilt and something else, something the Doctor couldn't precisely name. Then the moment disappeared. She smiled smoothly. As River looked from the Doctor to the stairs leading to the rooms, she said, "I wouldn't say I was tucking him in. He's seventeen! He was exhausted. I was just helping him to his room."

The Doctor knew he had her there. He hopped forward, bouncing on his toes and hooking his thumbs on his suspenders. "You fluffed his pillow," he said, jeering slightly. "You kissed him on the forehead!"

River's stare bore into the dashboard. She darted to the other side and the Doctor smiled widely as he peered at her through the wires and poles.

"River?" It was obviously a question this time – a request for acknowledgement. A minute passed, in which River busied herself with the TARDIS and the Doctor tasted blood on his bitten tongue.

Finally and suddenly, River pulled her elegant fingers away from the controls and locked eyes with the Doctor. "Is there something wrong with that?" she challenged. Her head tilted, eyes wide in supposed innocence.

The Doctor moved to stand beside her. Leaning against the console, he asked, "Why?" He crossed his arms, then uncrossed them and rested his palms on the edge of the dashboard. "You've always been rather, well, cold to him. Why the change?"

River gave a tired smile. Her shoulders drooped. "Spoilers," she whispered, her eyes streaking across the controls.

Nodding, the Doctor chuckled. "Of course." He watched River press her lips together and stroke the TARDIS. "There's nothing wrong with it," he murmured. His thumbs rubbed circles on the TARDIS.

Her smile quivered in perplexion. "Excuse me?"

Nudging her shoulder gently, the Doctor muttered, "I don't think he minds you being his mother."

River huffed, cleared her throat, and bowed her head. Her curls masked whatever expression was on her face. The Doctor wondered if she knew much about Hiccup's real mother. Hiccup had shown him pictures of a husky, tall woman with her wispy dark hair pulled into a tight ponytail. She'd radiated confidence. Hiccup would gaze at her pictures in longing and embarrassment. He tried to pretend those pictures were papers from his past. But of course, the Doctor knew better. It said something when the teen hadn't said goodbye to his father, but had snatched photos of his mother from his room.

Another minute passed before she spoke again. "I think I'll retire to my chambers. We can call it a day." She grinned in self-confidence before gracefully ascending the stairs. Her long, slightly torn red gown drifted around her ankles.

The Doctor watched her leave.