After the evening with the taxi driver case, Mrs Hudson made sure that Selena and Dave made themselves at home. She was surprisingly at ease with having Dave around, which reassured both him and Selena. The day after Selena's arrival in London and first case, she resumed her usual duties that she would normally get up to at home; making enough tea for the guys to swim in and making an attempt to sort out Sherlock's experiment equipment that littered the kitchen. Sherlock wasn't too pleased with it, but cleaning and tidying was a second nature to Selena, after filling a teapot. She was careful not to touch anything that looked to be in use or dangerous and put away the things that weren't. She was careful to double check however, for fear of ruining any experiments.

Dave appeared to take a shining to John; the doctor would often be seen giving Dave a lot of fuss and attention. Selena warned John not to give him too much pampering in case it turned Dave into more of a pet than companion. Sherlock didn't interact with Dave very much which puzzled Selena. Dave may approach Sherlock, but instead of offering his hand like most people would, he'd watch him curiously, observing him.

Throughout most of the day Selena got to know the crew 221B better, having little chats with them and asking questions. Selena picked up details about their lives, interesting things that they've done and events that happened to them. She divulged from bits of information their likes and dislikes on one or two habits of theirs. They certainly were an interesting bunch of people – John liked a little danger to keep his life exciting, but also takes any chance he can get to take a woman out on a date – Selena decided it would be a good idea to be wary of him. Although, Sherlock remained a mystery; he spoke very little making it hard for Selena to find out anything about him. All she got was that he liked to be well dressed and reads the news to try and find another case, which wasn't very much. Most of the time he seemed to be doing that deduction thing he talks about on his website, finding out what he can about Selena without saying a word.

By afternoon, Selena and Sherlock began having a more serious conversation about having her as his assistant. They sat opposite each other on the comfy chairs, Sherlock in his signature thoughtful pose with his hands clasped together, his eyes looking over the psychologist, observing and deducing. Selena sipped her tea feeling extremely self conscious. John sat at the desk on his laptop, busying himself with writing the blog his therapist suggested he should do. He would certainly have a lot to write about living with the world's only consulting detective.

Sherlock broke the silence between them, "Yes, I think you'll make a good assistant," he said confidently. "You have proved to be almost as clever as me, which is a good start. It would be nice having another clever person around."

John shot a vicious glare at Sherlock from across the desk. If looks could kill, that one would at least seriously injure.

"The cleverness stops when it comes to numbers, I'm afraid. Everything else I can probably do," Selena warned about her incapability of doing anything with numbers. "My brain doesn't like them."

"We can't all be good at everything I suppose. I'll leave you to the psychological behavioural stuff for a start while you acclimatise, since that is what you are best at. How good are you with self defence?"

The question came as quite a surprise to Selena. Why would she ever need to be good at self defence? "Erm...well, I'm not the naturally aggressive type. That would be Dave's speciality."

"I can see you'll have no problem defending yourself. The grass stains on your jeans and the way you dress say you did a lot of outdoor work, and that you dress for ease of movement rather than appearances. You're also well toned on the arms, so whatever you used to do required your physical strength. Doing what we do, we're bound to make a few enemies, so you may have to do a bit of fighting every now and then."

Selena almost lost her words, "Yep, well I was going to say that I am stronger than I look. Anything else you'd like to point out?" Sherlock appeared to enjoy showing off his deduction skills, so Selena allowed him to revel in his brilliance for a little longer.

It took a moment, but only a short one for Sherlock to deduce something else, "The calluses on the tips of your fingers suggest you play a string instrument and going by your style in your hair and choice of clothes, I'd say it's a guitar. Am I right?"

"Yep, everything right. I'd give you an A* if I could grade it," Selena complimented him.

He smiled a little and resumed asking more questions, "What about weapons?"

"I can handle guns. Smaller ones are easier for me, but have fired a rifle before." Sherlock nodded, satisfied, and John looked at her quite surprised. "Best hide the gun from you as well," he murmured.

"And one more thing, how do you feel about the violin?" Sherlock asked less seriously.

Selena raised her eyebrows at him, "Erm...it's alright as long as it's played properly. Why?"

"I play it when I'm thinking and sometimes I don't talk for days on end, would that bother you?"

"Not at all, it'll be nice to have a break every now and then," Selena teased.

"Excellent. Welcome to the team."

"Both of us?" Selena referred to her companion, and Dave looked up at the detective expectantly.

"Both of you."

Selena held back from being too overt in her happiness and giving Sherlock a massive hug and instead celebrated quietly with a party in her head, "Yay!"

"You're going to have to stay with us. I need you to watch what I do so you can learn."

"Ok, but aren't there only two rooms?"

"John will share with you."

Selena and John both turned to each other and said, "What?"

"I can always sleep on the sofa, I have slept in much worse places before," Selena looked back on one of her university evenings, trying to convince Sherlock that she didn't need to share John's room.

"The sofa isn't very comfy to sleep on; your shoulder told me that after you had a nap. Mrs Hudson has a spare mattress that you can use, but no actual bed, but that can be sorted out later."

"Okay...Oh there's something else; I have this thing, cyclothymia. It's a form of bipolar disorder. My moods can sometimes change dramatically from being quite euphoric to depressive, but it's not as bad as in bipolar 1, it just leads to a little...disruption – nothing to get too worried about. Is that a problem?"

"Not at all," Sherlock rose from his chair, "It will be quite interesting."

On that note, Selena went about sorting her living arrangements. With John's help, she dragged a single mattress along with a duvet and pillow to John's room, and made it as much as possible to resemble her bed at home – placed lengthways against a wall with the head end furthest away from the door. Dave decided he would sleep downstairs on the chair in the hallway, possibly to guard against any intruders that thought it would be a good idea to break in.

Selena brought her small suitcase upstairs and placed what clothes she brought with her in John's wardrobe that she also shared with him. The wardrobe was more than big enough to accommodate all their clothes so that was no problem. Since Sherlock wanted her to stay with him almost all the time to learn, Selena had to call her mother to send some of her stuff in the post. Going to get it herself would have cost time and money which Selena didn't have much of now that she moved into Baker Street. She only asked for the essentials, what she couldn't do without; clothes, one or two books that might prove to be useful, her laptop which had almost everything she could ever need on it, mostly music and of course, her guitar. Everything else she didn't really need or could be easily replaced. She also asked for Dave's two favourite things; his ball and tug of war toy. She and Dave shared fond memories with those items, not to mention it will stop Dave from becoming bored.

Psychologist and ex-police dog settled in very well over the following days. The possessions that Selena asked for her mother to send arrived in a medium sized cardboard box, the guitar separate in its case with a 'fragile' sticker on it. She unpacked the box, placing clothes in the wardrobe, books on the bookshelf and placed her guitar neatly in the corner of the sitting room wear Sherlock kept his violin and Selena sent her the money it would have cost in return. Her guitar was an acoustic one, the front of the body, which had a few stickers slapped onto it to make more personal to Selena, was a natural pale brown colour, while the sides and back were darker with a slight reddish tint. The neck and head wear a dark brown, almost black and shiny like the rest of the instrument. Selena didn't usually like playing with an audience but would occasionally demonstrate her musical abilities to Sherlock, who would also do the same with his violin. They both played different types of music, but nevertheless, they still enjoyed listening to each other's talents.

Selena would often take Dave out into Regent's Park which wasn't far from Baker Street and allow him time to run around in the open place and greenery which he enjoyed very much. She also became like an au pair to the lads, making tea, cooking, shopping and cleaning, because they couldn't seem to be bothered to do it themselves and that it made her feel more comfortable. This was when all was quiet and not much was going on in crimes and solving cases. The only thing that would disrupt Selena's usual duties would be one of Sherlock's weird experiments. It seemed that he needed pastimes that required thought, such as experiments and solving problems to prevent himself from becoming bored and his mind become restless, almost like one of Selena's hypomanic phases. Test tubes and Bunsen burners will cover the table, specimens of body parts in the fridge and chemicals in jars often in cupboards where there was food. Selena resorted to giving Sherlock his own personal cupboard and shelf in the fridge to keep all his experiment stuff, and a box where he should put equipment that isn't being used. Sherlock did question this behaviour, saying that he only appointed her as his assistant, not housekeeper. Selena could only reply with, "It's like a buy one, get one free offer; hire an assistant and you get au pair free! Besides, like doing domestic stuff."

The only problems Selena experienced were sleeping and finance. John had an annoying habit of snoring and occasionally had nightmares. Selena knew that he couldn't help it and tried to put up with it, but there came a point when she couldn't take it any longer. She went downstairs early one morning in her pyjamas with dark circles under her eyes and found Sherlock sat at the kitchen table, fully dressed looking at something through the microscope. Selena thought that he either got up extremely early or didn't actually sleep the night before, both of which were rather common. To remedy her lack of sleep, Selena asked politely, "Sherlock, would you mind if I moved into your room? John snores and has nightmares and it's driving insane."

Sherlock looked up from the microscope and hesitated for a moment, "Of course, if it will help you sleep better."

"Thank you," Selena sighed relieved, "I'm probably going to be sleeping for most of today, since I haven't actually had the recommended eight hours for days now. Surprised I'm not dead."

Sherlock chuckled at Selena's comment as she went back upstairs to remove her bed from John's room and relocate into Sherlock's room. She set up her bed in a similar way to before, opposite Sherlock's own bed and beneath a window. His room was surprisingly tidy. She expected to see something similar to the mess that was currently in the kitchen and a few more burns where things might have exploded. The only things on the walls were a poster of the periodic table and some Japanese thing that Selena couldn't figure out. There she slept for most of that day until she felt she had made up for sleep she had lost.

The other problem was money; Selena got by on Jobseeker's Allowance which only gave her about £50 a week, although she kind of had a job but apparently apprentice consulting detective doesn't count as a job, much to Selena's annoyance. John didn't have a job either, and Sherlock only got paid if whoever he was doing a job for offered him money for it, except money didn't pose any interest for him which often led to him not accepting it.

Once he was satisfied that Selena had settled in, Sherlock began lessons in order to teach Selena and set her up for being a detective. They started with the basic things that Selena was weak on such as her mapping skills and natural aggression. To overcome these weaknesses, Sherlock would take Selena around London showing her the streets and landmarks that would help her to determine where she was if she ever got lost. He also made sure that she absorbed as much information as possible so that once they got back home, she would be able to recite as much about their journey as possible. It wasn't an easy task for Selena but she did slowly improve.

Sherlock also thought of the idea that aggression is encouraged by frustration, and so attempted to bring out Selena's more aggressive side by making her feel frustrated. Selena, being a psychologist understood the principle and realised that Sherlock was using her as a participant in an experiment. Selena would have to do a little experimenting of her own one day. To stimulate frustration and thus, aggression, Sherlock would deliberately do things to annoy Selena, such as leaving his equipment out on purpose, making a lot of noise while she was trying to sleep or just behaving like a general moron. Once agitated enough, Selena would have to channel her aggression into either verbal aggression or physical aggression, which consisted of shouting abuse at either John or Sherlock, squeezing a stress ball or firing John's gun at target, much to displeasure of Mrs Hudson. With the correct amount of frustration, Selena would be more aggressive than she was previously, but too aggressive that she became antisocial. All the while, Sherlock would record data from Selena's reactions and behaviours. Once he decided that enough of the 'treatment' had been administered, he placed Selena in a fake situation, without her knowing, with John posing as a burglar breaking into the flat. Dave was kept out of the way so that he didn't interfere. Selena reacted as expected, first warning the burglar verbally and with the threat of a weapon. The second step was to see if she could use her naturally occurring strength and newfound aggression to overpower the burglar into submission. This was done superbly by knocking him off guard with a blow to the stomach, tackling him and pinning him to the floor. Sherlock concluded that his experiment had worked and that it is possible to encourage a certain amount of aggressive behaviour in a person, at the cost of causing his friend a few bruises.

Once the basic lessons were finished, Selena would move onto the more complicated stuff - the deductions and the forensic stuff that she will likely have to use in a case, or, if something interesting turns up, her first full case.

Dave continually tried to interact with Sherlock since he and Selena had moved in, but to no avail. It wasn't until Sherlock actually expressed his confusion to Selena that some interaction occurred. "Why does he keep doing that?" he asked.

Selena peered over her laptop screen, "He's waiting for you offer your scent."

"What? Why?"

"It shows to him that you are his friend and he'll be able to recognise you by smell," Selena explained as if it was something everyone should know. "Have you never had a pet before?"

"No, it never interested me."

"Not even as a child?"

"Mummy didn't like animals. She said they were dirty and we weren't allowed them, so I never had to desire to keep a pet."

"You are missing out on so much."

Sherlock continued to observe Dave, as if pondering what to do. After a few moments, he offered his hand to Dave, who cautiously sniffed taking in Sherlock's scent, cataloguing into recognisable scents of other people. Dave licked Sherlock's hand in thanks. Sherlock seemed surprised by this – pleasantly surprised. He hesitantly began stroking Dave's coal black fur, the Alsatian wagging his tail in contentment. Dave rested his head on Sherlock's lap and Sherlock smiled involuntarily from the effect that stroking an animal has on people. Neither Selena nor Sherlock needed to say anything to understand that he quite liked Dave and would soon consider him as a friend. Selena smiled, pleased that she managed to solve Dave's problem and bring Sherlock a new companion both at the same time. Dave now considered the people at 221B his pack and would be as sociable and loyal to them as a wolf would with its own wild pack, not to mention how useful Dave could be in solving cases with strength and senses like his own.