Eurus followed behind Sherlock and the children silently, making sure to softly match her steps with his. Her petite, light frame made it easy for her to mask her presence, and he was already pre-occupied with Rosie and Will. Still, she didn't want to risk him noticing that he was being followed. She waited until Will began to fuss, and then quickened her pace to catch up.
When she was near enough she began to sing.
"Hush little baby, don't say a word, Auntie's going to buy you a mockingbird…"
Sherlock stopped dead in his tracks. Eurus? But that was impossible, she was secure at Sherrinford. Slowly, he turned around as his baby sister caught up to him.
"How…?" he said softly, watching her in shocked amazement as she approached her nephew, still singing to him with her angelic voice. Sherlock stared down at her as she reached down and pulled Will out of the twinned pushchair he shared with Rosie. Immediately, the young boy calmed down as he felt his Aunt's familiar touch and heard her voice.
"Oh, the how isn't important Sherlock, only the why. Sometimes you forget that, brother." She smiled up at him. Sherlock blinked rapidly.
"Alright, then." Sherlock, still confused and a little shocked to see his sister in front of him, free as a bird, pursed his lips, thinking, but came up with nothing else to say. He placed his hand on her back and gestured for her to continue their stroll with them.
"You know Sherlock, I'm amazed you haven't found it criminal that a person who was driven to do such terrible things through loneliness and jealousy has been kept in solitary confinement for decades." She brushed her cheek against Will's silken dark curls, taking in the sensation of innocence and the smell of his baby shampoo still lingering. His hair had gotten longer since Sherlock and Molly had last visited her at Sherrinford with their son.
"It doesn't seem a very effective way to eliminate the underlying problem, does it?"
Sherlock looked down at her and smiled. "No, indeed it does not. I suppose Uncle Rudy didn't think that far ahead when he placed you there. And Mycroft obviously didn't think of it at all." He shook his head. "I confess, it didn't occur to me either, I'm afraid. I am so sorry for that, Eurus."
Eurus laughed softly, dismissing the apology. "Why would it occur to you Sherlock? You didn't even remember that I existed, let alone know where I was and the conditions I was being held in. You've done your best to help me in spite of everything I did to you and John and Mycroft. You at least understand that solitary confinement isn't the answer for someone who is lonely and abandoned. It isn't your fault that you can't change my circumstances, after all."
Sherlock nodded, spotting a park bench ahead. "Come, let's sit. I think Rosie wants to stretch her legs."
Making their way to the bench, Sherlock said, "No, I suppose you're right. I still feel though that… if I hadn't been so dismissive all those years ago, perhaps…" He reached down and pulled Rosie out of the pushchair, setting her down on her feet. Almost immediately, she ran over to a patch of wildflowers growing nearby.
"You can't change the past, brother. You can only do what you have already been doing. Changing the pattern. I know it sometimes appears that I am beyond reaching but I'm not anymore. You are no longer dismissive and only interested in playing pirates with your best friend." She smiled inwardly as Sherlock wrapped an arm around her shoulders, giving them a squeeze.
"No, I suppose I'm not, am I. By the way, speaking of change... according to the rules, the adult holding the baby is in charge of changing their nappy." He winked at her and grinned broadly as she stared at him, confused.
"Nappy? But he doesn't need his…"
"Incoming in four… three… two…one…" Sherlock counted down with a gleam of mischief in his eyes and a playful grin as Will's face scrunched ever so briefly, a tiny grunt coming from his throat. "That's my boy," he murmured, reaching over to tousle the curls.
"Oh…" she exclaimed, her eyes growing wide, just as Rosie returned with her tiny fist full of wildflowers. The tiny blonde girl presented them to Eurus, smiling and giggling.
"You may want to take those. Just. Saying." Sherlock grinned at her, his eyes aglow with laughter.
"Fortunately, you have experience changing nappies, don't you sister?" Sherlock continued. Eurus smiled at him, puzzled and intrigued. "You bear a faint scent of hand sanitizer and baby powder, which did not come from my son as his shampoo smells of lavender to help him sleep. Additionally your fingernails have traces of glitter glue, and there is a small piece of craft paper stuck to your sleeve. I'd mention the spot of pureed peas on your ear but I'm sure my point has been made. Which daycare is it you've been to?"
Eurus laughed out loud, handing her bouquet of wildflowers over to Sherlock to hold for her. She reached into the bag to retrieve the necessary supplies to change her nephew's nappy, and began to regale Sherlock with her adventures.