A/N:

Harry Potter Halloween Collection Prompt: (title) Let The Right One In

Marlene heard the familiar scratching at the door, not for the first time that week. Whenever Sirius had a particularly rough day, he took on his dog form before coming home. "I don't know, I just feel safer, more relaxed that way," he'd told her. And the days had been quite rough lately. There were more disappearances and more people were dying every day. She found herself greeting Padfoot more often than Sirius.

He wasn't lying about being home late, she thought. She'd waited up until midnight for him and then gone to bed, falling asleep within an hour. She guessed that it must be at least three or four in the morning. Sighing, she threw off the blanket and trudged down the stairs.

"You're lucky I love you," she grumbled as she opened the door. "I was warm and comfortable." He looked up at her, his tail wagging. "Well, come on then. It's freezing out there." She motioned him inside and he trotted in.

Marlene closed the door and leaned against it, covering a yawn with her hand. "You could've transformed after you let yourself in, you flea-bitten mongrel. Oh, come off it, I was only joking." He was giving her those sad eyes that she always gave in to, which were ten times worse when he was a dog. "Let's go."

She climbed back up the stairs, Padfoot following close behind. As soon as she was in bed once more, he jumped up onto the bed and burrowed under the blanket, snuggling up as close to her as he could. She put an arm around him and was quickly asleep.

"Um, Marlene?" She found herself awake again too soon. It was still totally dark outside.

"What?" she mumbled. She hugged him tightly, enjoying the warmth of his fur against her skin. His fur? Didn't he just say something? How...

"You do realize that's not me, right? Please tell me you didn't decide to get a dog."

She pushed the dog away, falling out of bed as she backed away from it. Sirius, who had been standing by her side of the bed, caught her. "I thought it was - I could've sworn -"

The dog, none to pleased with being disturbed, sat looking at them both. This seemed rather menacing to Marlene, as the dog's face wasn't visible in the darkness.

"You sly thing," Sirius said, chuckling. "I've been seeing him around the neighborhood lately. He's just a friendly stray, I've talked to him a few times. Must be he was watching me as well."

"So you're saying -"

"He's smarter than he looks. He's seen me coming and going. He knew you'd let him in because he looks almost exactly like me. A warm place to sleep, maybe some free food...what stray would turn that down?" He patted the dog on the head. "You can stay for the night, only because I'm too exhausted to care. We'll see about finding you a home tomorrow." The dog wagged his tail in response, then curled up at the foot of the bed.

"Yes, please," Marlene finally spoke. "I want to make sure I let the right one in next time."