A/N: Once again: Thank you all you lovely people! You are amazing!
So let's find out who this Mary Poppins is...

Hours later Molly Hooper laid on her bed in her hotel room with one hand draped over her eyes when her phone on the bedside table vibrated, indicating a new message. The television was turned on, but she had not bothered to pay attention to it about an hour ago. There had been nothing on that could've taken her mind off the things that had happened in the morning. Therefore she had decided to just keep it on to have some kind of background noise.

Around noon she had gone to the Chinese restaurant around the corner in order to get something to eat. She had ordered some noodles for take away planning on eating it in the park. The fresh air and the walk to the park had helped her to clear her mind a bit and she had sat down on a bench across the small lake and had looked at the ducks swimming there. But when she had opened the box containing the food, the smell had made her feel sick and she had ended up throwing the noodles away untouched. She had not felt like eating. She had not felt like doing anything at all at that point. Maybe like crawling into a hole and dying from her misery, but since there was no hole in the park…

After a long time sitting on the park bench, staring blankly ahead and being lost in thoughts, she had suddenly realised that it was getting dark. Not wanting to be out alone in a park at night, she had gone back to the hotel, had turned on the TV and had waited for the case to be over, so that she finally could go back to her flat to have a good long cry with a lot of ice cream and figure out the best way to never cross paths with Sherlock Holmes again and still keep her dignity. She had no illusions that he would make it easy for her.

She rolled over to grab her phone. Not surprisingly the text was from the man next doors:

THEY GOT THEM. LOBBY IN 5. SH

She did not bother to text back. She knew he did not expect her to. She rolled off the bed, put on her coat, took her bag and left the room, dreading to meet the consulting detective in the lobby.

The black-clad figure that was Sherlock Holmes was standing with his back to her when she exited the lift in the lobby. She steeled herself for a hostile glance or a techy statement about her taking so long, but he only acknowledged her with a simple nod when she reached him. He went outside to a waiting cab, and she followed him.

The first minute of the taxi ride was spent in total silence, and the air was so thick one could cut it with a knife. Molly felt the urge to say something, but made herself stay silent. She was determined to follow through with her plan of distancing herself from the consulting detective.

When the silence was almost too hard to bear, Sherlock finally broke it, "They've found the children together with Mary Poppins in an abandoned warehouse near Canary Wharf."
Molly could not help a relieved sigh that escaped her. "Are they ok?"
"Yes." He did not show any emotion. Molly did now know if he was glad about it, but she figured he plain did not care.
They would soon reach the Banks' residence, so she wanted to ask some other things before they would be surrounded by police.
"Did they find them by tracking Bert?"
"Yes. He led them straight to his partner in crime. Seems like he's not so intelligent after all." It was plain as day, the subtext being, "Not as intelligent as I am."
The next question was one Molly dreaded to ask, but she just had to, "And what about... Moriarty and the Supercali… You know…"
There was the smallest of smiles tucking at the corners of his lips, "You'll see."

The taxi stopped, Sherlock paid the cabbie and rounded the car to join Molly on the pavement. The neighbour with the white beard and the sailor hat sat at his illuminated window again and looked down on the pair on the pavement. He shouted and pointed a finger at them, "The wind is about to change again! The wind is about to change!"
Sherlock rolled his eyes and went towards the door while Molly muttered, "Everything's higgledy-piggledy here."

As expected Lestrade and some police officers Molly did not know and Sherlock did not like (or better did not bother to acknowledge their presence) were gathered in the sitting room. Mrs Banks ran over to them as soon as they entered the room. She threw her arms around Molly and hugged her tightly.
"Oh Dr Hooper, I can't thank you enough! Thank you! Thank you!"
She repeated her words numerous times, and out of the corners of her eyes Molly could see Sherlock watching the scene with disdain. He was probably afraid Mrs Banks would want to hug him as well. But as soon as she released Molly from her fierce embrace and her eyes wandered over to him, he knew he was safe. She held herself high when she made a step towards him and extended her hand. "Thank you very much, Mr Holmes," she said formally and shook his hand. He knew she had not forgotten how he had treaded Molly today, and probably never would. Mrs Banks felt strong loyalty towards other women who were treated badly by men. Therefore he may have earned her gratitude for bringing her children back, but had lost her respect forever. But that was fine with him. It was not her whose respect he wanted, it was the respect of the woman next to him he feared to have lost.

Mrs Banks turned around to the party of people behind her and it did not escape Molly's notice that she was wearing her "Votes for women"-button. Her husband walked over with one child at each hand. He seemed to hold onto them very tightly. His posture was as stiff as ever, but his features had softened noticeable. He looked down at the children with an affection Molly would have never given him credit for when he said, "Jane, Michael, I want you to meet Dr Hooper and Mr Holmes. Thanks to them you're back safe and sound."

Mr Banks pushed the kids gently forwards to thank the pathologist and the detective. They looked shy – even a little frightened. Molly could not blame them. They had gone through a traumatic experience. In order to lessen their fear, Molly crouched down onto their level and extended her hand.
"Hello Jane, hello Michael. Nice to meet you." She smiled a warm smile, and Sherlock could only watch in wonderment as the faces of the two children beamed up and one after the other shook her hand. The next second one of the hands (Jane's to be precise) was held into his field of vision. He stared at it for a moment as if not knowing what to do with it. He felt Molly nudge his leg with her elbow and that brought him out of his stupor.
"Hello," he said and shook Jane's hand stiffly. He repeated the action with Michael. The children eyed him curiously and then looked back at Molly who had stood up again. She smiled again at them and nodded as if they would share a private joke. Sherlock could not help but feel a bit excluded.
Behind the children Mrs Banks cleared his throat, "Isn't there something you forgot, children?"
The two looked at Molly and Sherlock. "Thank you Mr and Mrs Holmes."
Molly's eyes widened when she felt Sherlock's posture going rigid beside her. She inwardly prepared herself for another outburst, but was more than surprised when she heard his calm baritone say, "No problem."
She drew a breath she didn't know she had been holding.
"Come on you two, it's late. Let's get you to bed." Mrs Banks took her children, nodded at Molly once more in thanks and exited with her children in tow.

So far Mr Banks had not expressed his gratitude, and Sherlock knew he would not. He was way too proud to admit that he had been wrong. And that was one of the few things Sherlock could understand. Sherlock did not need his gratitude or even his money. He had needed a case and Mr Banks had provided him with one. They were even.

Finally Lestrade walked over to them.
"Molly, Sherlock good to see you teamed up again."
Molly felt the temperature drop to zero the moment Lestrade had finished his sentence, and she looked down onto the floor. Obviously Lestrade could feel it too, because he looked curiously from the pathologist to the consulting detective. Sherlock did not like that at all, so he asked in an irritated voice, "So what's her real name?"
Lestrade refrained from trying to find out what was going on between his friends and looked Sherlock in the eye.
"They don't know. She's been there for almost 5 years now and they still don't have a clue what her real name is or where she comes from."
Sherlock sounded frustrated, "This is impossible. There must be some clues."
Lestrade shrugged. "There may be, and if you're interested be my guest and have a look at them."
Sherlock looked disgusted. "No. I don't have time for that nonsense."

Molly had been looking from one man to the other during their conversation, having no idea what they were talking about. She crossed her arms.
"Would anyone be so kind as to enlighten me?"
Lestrade turned towards her. "Yeah sorry, I thought Sherlock had already told you."
"There was no time," the man in question defended himself.
"Whatever," Lestrade began, "Sherlock had the idea that this whole Supercali…"
"Supercalifragilisticexpialidocious," Sherlock completed.
"Exactly that," Lestrade went on, "may have come from someone who is mentally ill. Therefore we've sent Mary Poppins' facial composite to all the sanatoriums in London and we actually had a match in Bethlem Royal Hospital. She goes under the name Mary Poppins there as well, since nobody knows her real name. One day she showed up on the doorstep of the clinic with her umbrella and carpet bag in hand and told them her name was Mary Poppins, she was a practically perfect nanny and she would stay until the wind would change." He shrugged, "They figure she suffers from some personality disorder, for all questions the doctors have asked her, she's answered with the Super… you know… word. We went to look at her room. The walls are full of it. It's quite creepy." Lestrade shivered. "She even shouted it the whole time when we arrested her."
Molly thought about it for a moment. "So this was all the doing of a mentally ill woman?"
"Yes."
"But what about Bert?"
Now it was Sherlock's turn to explain, "He was one of the nurses. Somehow he sympathised with Mary Poppins, and they came up with the plan to kidnap some children in order to get money. That's how she could escape from the clinic – he helped her."
"We live in a sick world." The grim voice of Mr Banks made them turn around towards him. Molly had been so absorbed in Lestrade's and Sherlock's explanation that she had almost forgotten that there were other people in the room as well.
Lestrade sighed deeply and walked over to the other police men who were standing in the corner of the room.
Sherlock made a step towards Mr Banks and extended his hand. Molly was surprised by his gesture. And so was Mr Banks, because he eyed it suspiciously before taking it and shaking it while Sherlock announced, "I'd say our work is done."
Mr Banks nodded, and they released hands. He came towards Molly and shook her hand as well. "Thank you very much, Dr Hooper. Take care." She smiled friendly and nodded as well. She still did not like him, but she had the hope that he might have learned something from this horrible experience and would be a better husband and father from now on. Maybe she was being silly believing in the good in people, but that was just the way she was.

She turned to follow Sherlock who was waiting for her at the door, when she heard him say, "Just though you know Mr Banks, we'll need to visit your roof once more."

Before Molly could even say a word he had exited the room, clearly expecting her to follow him.