Sophie had two sets of keys to Craig's house.

That was it then. That's how he felt about her. It said it all.

The Doctor pressed the TARDIS key harder into his palm. The ship was different, but the key had remained the same. This one hadn't always been his. He'd given keys to his friends before, but this specific one he had given Rose. He closed his eyes, seeing the day he had given it to her.

Her hair was up, her eyes down, watching the floor as she stepped behind him into the TARDIS. He had turned and was looking at her, eyebrow raised and arms crossed, for a number of seconds before she looked up at him. She sighed.

"Fine. You were right about him. Happy, Doctor?"

"Why'd you give him the key?"

She blinked. He didn't like how wide her eyes were now. It was part surprise, part indignation, and it looked like he was going to lose his higher ground before this argument even began.

"Excuse me?"

"Why did you give him the key, Rose?"

Neither spoke for a moment as they stared each other down. Then he continued, "I trusted you with that key."

"Well I didn't know he was going to be an idiot!" she protested, voice shrill.

"You've got to be careful who you give that to." His voice was low and steady, and it made her even angrier. He sounded like he was speaking to a child.

"It's not like I give it to everyone."

"What if you had needed it?"

"I was with you!"

Their eyes remained locked, both flaming. Eventually she closed her eyes and breathed deeply. "I thought…I thought the TARDIS—I thought the key was for me too—" She stopped and shoved her hand into her pocket. "If it's not mine, I don't need it. I'll prob'ly just be with you anyway."

He held his palm up to her, opening his mouth to object, but she pushed the key into his hand and his fingers enclosed it automatically. As she stormed to her room, he stood there, holding the key as far from him as possible.

He didn't see her for hours. The TARDIS cooked her dinner and propelled the scent throughout the halls. For his part, the Doctor sat at the table (and he'd avoided just sitting in there for centuries before she'd shown up) and waited for her to give in.

He's sure she was hungry long before she emerged (she's stubborn, but then, so is he; he likes it about her), but finally she did. She didn't look angry anymore, just sad. Somehow, that was worse.

"Rose—"

"Save it, Doctor. If you don't want me handing the key out, it's fine. I just thought…"

He stood up and held the key out to her. "Okay. Don't hand this out."

Avoiding his eyes, she nodded as she took the key and pocketed it. He hooked a finger under her chin and lifted her eyes to his. Between them, he was dangling a second key right above her nose.

"This one, though…" She smiled softly as he laid it in her palm. "If you want to lend this one out, it's fine. Just be careful, all right?"

She nodded. His arms wrapped around her waist and pulled her into his chest as she burrowed her face in his jumper.

"It's your home too, Rose," he had told her.

She had grinned, and eventually lent the key to Jack (until the Doctor finally gave in and gave him his own), her mother (only for a few minutes to retrieve something), and Mickey (he'd changed his mind and decided he'd just stick with her). She'd had the spare with her inside Torchwood as she'd temporarily lost hers in a pile of dirty clothes. He hadn't had the heart to clean it up, but the TARDIS had taken care of it and left the key on his dresser, where he found it after he left Donna at home.

Opening his eyes, he slipped his hand into his pocket, still wrapped around the key. He smiled as he moseyed back to his ship.

His home, really. He'd have no reason to give a friend the key to his car.