It was peaceful in the neighborhood where Natasha Romanoff did her daily workout sets in the backyard. She hated how exposed she was to the outside world, but since her basement had flooded there wasn't room for her mats anywhere else. So for the past couple of days Natasha had simply dealt with it. Her career as an assassin-turned-spy may have been short-lived, but that was no reason to be out shape. She left the 'in case of an attack' out of her reasoning though, as it tended to make her government-assigned therapist sigh disappointedly. The disappointment she could handle, the call through to Coulson she could not.
Natasha, even after almost five years of retirement, considered herself to be quite vigilant regarding anyone approaching her vicinity. Apparently she was wrong, as she felt the touch of something solid on her leg mid-push-up. She launched herself up and back, spinning to settle into a defensive position, ready to take out the threat. Standing there was a dog, tongue out and looking quite calm. She scanned the yard for any possible owner or companion, but saw no other life forms. The dog had moved closer in front of her, she eyed it skeptically but stuck her hand out anyway. The dog licked her fingers and she scratched its head. This wasn't so bad. Its collar yielded no information as to an owner or address, and the dog didn't seem inclined to be leaving any time soon, so she shrugged and headed inside.
The dog followed her into the house, tail wagging slightly, and it occurred to her that the dog was probably somewhat elderly. The dog - male, she could see from this angle - slowly walked down the hall, curled up in the corner and fell asleep. Natasha fixed herself some tea.
The next day the dog was back. She scratched him around the ears and let him into the house before resuming her workout. Absently, she considered the chances of him being a spy dog, but quickly dismissed it; those were long out of fashion.
On the third day she put a folded up blanket in the dogs corner and left the door open before starting her workout. Natasha was disheartened when the afternoon passed without a single golden hair to be seen. She tamped that feeling down; she'd only met the damn thing twice and already she was considering him a friend.
The next day he was back and she gave him a very rigorous ear-scratching.
It wasn't until a few weeks later that Natasha thought to be curious about the dogs origins, so stopped him on his way out and scribbled a note to pin to his collar: 'I would like the owner of this dog to be aware that almost every afternoon your dog comes to my house to take a nap. I would like to who you are and possibly the reason for this.' There. That was polite enough. She pinned it on with a safety pin and sent the dog on his way.
The next day the dog arrived for his nap, with a different note pinned to his collar: 'Lucky (the dog) lives in a house with 5 children, 3 under the age of 4 - he's trying to catch up on his sleep. Can I come with him tomorrow?' She finally had a name for the dog, and a reason for his presence, but was she curious enough to actually meet his owner? She mulled it over and came to a conclusion. Natasha pinned the simple response to Lucky's collar, mostly positive she made the right decision: 'Yes.'