Upon his arrival back at Baker Street, Sherlock did not hesitate to get to work. He opened John's laptop - John's was faster - and went immediately to a reliable search engine. Then he took out the small leather-bound booklet that he'd acquired at the café, and opened it to the first page, where a blonde, familiar-looking woman's picture stared back at him. He made use of the search engine for the next thirty minutes by typing in its contents:

"Surname: Ross

Given Name: Thalia

Nationality: British Citizen

Date of Birth: 19 Jan 77"

The inside pages, he noticed after he was done with the laptop, contained a number of stamps, where three different ones showed up periodically, Ireland among them. The very last page contained this:

"If this passport is lost, return to this(these) emergency contact(s):

Mr. James and Karen Ross"

…under which was a residential address in Guildford. He scrutinized the passport more closely for a moment, deciding whether or not to try running DNA tests on it at St. Bart's - but considering that he now had her name, age, and an address for what was most likely her parents' house, he figured he had enough of a basic identity. He could always get his brother to run background checks later.

For now, he texted John.

Her name is Thalia Ross. SH

John replied almost immediately.

The assassin? Really?

Sherlock didn't reply, as it didn't warrant an answer. He set the passport on the desk, before taking the seat in front of it. He studied it until John texted back again.

How do you know?

Sherlock smirked at himself.

Got her passport. SH

There were a few moments of silence where Sherlock imagined him slowly processing the information. He savored it.

How?

Sherlock chose not to answer, knowing what his applied methods would insinuate. He had, after all, let go of a murderer who killed an average of five people a week. Lestrade would have his head.

Right. I'm on my way.

He replied immediately.

No need to leave the surgery, John. I'll still be here when your shift is over. SH

Sherlock stood, still in his coat and scarf, and stuffed the passport back in his pocket. He wasn't lying to John; he would be at 221B when he returned. Between Point A and Point B, however, he couldn't promise the same.

Fine. Have you told Lestrade?

He'd expected that, of course, but it still made him pause in walking out of the flat. He didn't plan on telling Lestrade - at least not yet. This case was different from the others in that he couldn't simply sack the criminal based on her mistakes or on the evidence she left behind, because she was too good at her job. He was sure that she had killed plenty of people where the evidence she left made it all so obvious (every killer starts somewhere, right?), but those murders had been "solved" and tossed so long ago that they didn't matter anymore. The only incriminating evidence he could pull to have her arrested would be finding the base of operations of whatever her business was, or catching her DNA on a committed murder, which she had gone to great measures to ensure did not happen.

But now he had her passport. This gave him almost everything, assuming she hadn't lied or had her permanent files deleted. His course of action now was, first, to go to the only given address on the passport and extract whatever information he possibly could from its residents, and then, if that didn't work, to convince Mycroft to run background checks on the name "Thalia Ross".

Sherlock, please tell me you told the police you found a murderer's passport.

Sherlock sighed and let John go unanswered yet again. He would figure out eventually what the silence meant.

It was still fairly early when Sherlock arrived in Guildford an hour later, and considering how badly he and John needed the money, this meant he had, maybe, five hours to take care of business before he needed to beat John home. He figured he could be done in under two hours - that is, if one of the "emergency contacts" was actually home, or if the contact was completely made up. But he didn't expect either to be the case; it was 11 am on a Saturday - the only people not at home were ones like John, who were tired of their flat mates and in desperate need of money.

Guildford was a pretty little country town, not unlike the other country towns surrounding London. The buildings were old but kept up, and the town prided itself in whatever little history it had. It was relatively easy to find one's way around, though, and Sherlock was able to walk to the passport's address in very little time at all.

It was a large, white, two-story house with a long pathway and a trimmed yard. There was a shiny black car on one side of the driveway, but recently-made tire tracks on the other side told him there was another car that was currently absent. It wasn't hard to tell from all of it that the owners had a substantial amount of money. None of this surprised him.

The research he had done online before coming to Guildford had told him that James and Karen Ross were indeed the assassin's - Thalia's - parents. James Ross was employed as a doctor in the local hospital, and Karen Ross stayed at home and maintained the house, though she used to be a journalism professor. All this and more he had found hacking into the less-secret files of various psychiatrists that had had Thalia Ross as a patient. In thirty minutes, it was all he could manage to find without being too illegal, but it was more than enough.

He walked up the path to the front door, noting the value of the knocker and the like, before knocking on the door. He stood straight and cleared his throat, and then the door opened.

A woman, not much older than fifty, stood in the doorframe in a jumper and khaki slacks, with an apron hanging from her arm. Her demeanor was overall kind and simple, and not at all suspicious of him. She merely regarded Sherlock in a mildly surprised manner. "Hello," she said. "Can I help you?"

"Mrs. Ross, is it?" asked Sherlock, easy but business-like.

"Yes." She absently folded the apron in her arms.

"You remember Dr. Lawrence?" asked Sherlock. The name belonged to Thalia's last psychiatrist, who was well known for checking up on his patients often. "Dr. Lawrence Foley?"

"Yes, I do," said Mrs. Ross with a nod. "Are you his assistant? I'm not sure I remember you…"

"I'm his new assistant, yes. I'm Dr. Bancroft," said Sherlock. He'd thought the disguise would be a long shot, but the woman's simple-mindedness more than made up for any faults he had in it. He almost smirked at how easy it all was. "Just checking up on Thalia. "

"Ah, well, come inside, won't you?" asked Mrs. Ross with a smile, opening wide the door and allowing Sherlock into the foyer. She led him to the living room and gestured to a chair. "Would you like some tea? The kettle's already boiled."

"Tea would be lovely, yes," said Sherlock. He looked around the room once, noting the mild paintings on the walls and the high-end furniture. Their medical careers certainly had them well off, though he wondered how good this fluttery woman had to have been as a professor in her days, considering how easily she trusted that this stranger was merely making a house call unannounced from a psychiatrist they hadn't employed in over five years. It had definitely been a stretch of a story to tell, though Sherlock hadn't had a doubt in his abilities to pull it off.

Mrs. Ross came back from the kitchen with a silver tea tray in hand. She set it down on the coffee table in front of Sherlock, poured them both a cup, and sat on the settee on the other side of the table. She regarded him kindly. "Dr. Lawrence used to call to make his check-ups," she said, not in a way that she was suspicious, but just as passing conversation. "I've always said how much better it would be to make house calls. Phones are so impersonal, I think."

Sherlock nodded. "The doctor is trying it out," he explained and then chuckled, "but of course he's having me do the test runs before he will."

Mrs. Ross laughed and then sipped her tea. "He was very practical about everything, I remember…"

"Yes, and still is," he said curtly. "So, on to this check-up, I think…. I'm guessing Thalia's not around, present?"

"Oh, no," she said with a sad smile. "No, she lives in London. Moved out there to go to college and never came back." She laughed, the sound tinkling in the air similar to her china cups on their saucers. Her voice spoke of her age.

"What did she go to college for?" asked Sherlock. He took out a small pad of paper and a pen, more for show than to actually write down anything he'd find useful. He only needed his mind to have this conversation memorized. "I'm afraid Dr. Lawrence didn't send me with her file…"

"Oh," she said, "she went to study chemistry. Wanted to be like her dad, I think, but not exactly, you know? Or maybe he just steered her that way…"

"She spent a lot of time with him?"

Mrs. Ross gave another sad smile. "Her father and I split up when she was twelve, and she went to live with him until we came back together. She was seventeen, I think, when James and I reconciled."

"That's right," said Sherlock. "I remember seeing that in the file. What is it she does now?" He refrained from holding his breath, knowing how unlikely it was that Thalia would have revealed her true occupation to her parents.

"She's an accountant for a medical clinic somewhere in London," she explained, and there was no doubt that she believed it. "She doesn't like to talk about it much. I think maybe she's disappointed that she never made it as a chemist. Her grades just weren't up to par, you know, and she had such trouble in school." Her brow creased as she remembered, and pain fluttered in her eyes for a moment before she looked back up at her guest.

"What sort of trouble, Mrs. Ross?" He attempted to sound sympathetic.

Only then did she seem confused. "Dr. Lawrence didn't tell you that much? Why, that's why she saw him so much to begin with."

"I am sorry," said Sherlock. "I only started last week. I've been very busy with his current patient's files, you understand."

"Oh, yes, that makes sense," she said, and waved it off. She cleared her throat and stared into her teacup, remembering. "Well, she'd always been a little different, to put it plainly. It's hard to explain how, when she was a child…"

Different, indeed, he thought. I can only imagine. Sherlock leaned forward almost imperceptibly, listening attentively to the way she described her troublesome daughter. Inflection, sometimes, was everything, even when the speaker was as much an open book as Mrs. Ross.

"…but I think, subconsciously, we sort of knew," she explained. "She spent a lot of time outside, but never played with any of the other kids. She often told us they made her angry or nervous, and avoided them. She came across a dead bird one time-" here she took a sip of tea and grimaced "-and, well, dissected it, of all things. It got a bit worse from there - it wasn't the only time we found her doing something like that."

"She dissected other animals after that, you mean?" asked Sherlock, only asking to hear her say it.

She hesitated. "…Yes. Cats and dogs. A snake. That was when we started taking her to psychiatrists; her teachers noticed how… odd she was." She took another sip, and he copied the action. Then she put her cup and saucer down. "We always tried everything they suggested to help her, but I don't think any of it worked. We even transferred her to a private elementary school, which, admittedly, didn't do her any better. And it just went downhill when she started high school."

"How do you mean?" asked Sherlock. He wrote down some false notes.

"You see, she never made friends," Mrs. Ross responded. "But she met some people - some awful people, I think - and suddenly she was going out almost every night and she would be gone all weekend, sometimes, telling us that she was going out with 'friends.' But then she would report to her psychiatrists that she 'hated people in general' and had no interest in relationships. We'd thought at first that it was all a good thing, that maybe she'd actually made some friends but was too shy to say anything about them. Then, one night, we got a call from the hospital, who told us our daughter had severe alcohol poisoning coupled with an intake of some mysterious narcotic solution."

His brows rose in honest surprise, but he recovered quickly. "Did it stop after that?"

Mrs. Ross shook her head sadly. "It continued to get worse, and it seemed that nothing we did to help worked," she confessed. "Her psychiatrists said it had nothing to do with her father and I, and our divorce, but that she just had something in her brain…" She paused, putting her hand to her chest, the thought obviously causing her some pain. "Something wrong in her brain that made her… 'crave self-destruction,' as they put it." She sniffed. "Later they told us it wasn't just that, but all kinds of destruction, only she didn't indulge in causing any… pain… to others.

"It became almost a regular routine. Some weekends she would need the emergency room, others she would come home in the wee hours of morning and sleep, literally, for an entire day. Some days she wouldn't eat, others she wouldn't speak, but then sometimes she would read and study all day. She kept her grades near perfect, but she did all kinds of horrible things…. She got into fights a lot, too. Terrible fights, often with boys."

"How did her school take her?" he asked, jotting down more notes.

"Expelled her, suspended her," she admitted, frowning. "We had her transfer schools quite a lot - I think close to five times, as a teenager. Private schools were better for her as a teenager than when she was a child, but there were always the same problems."

"So she had alcohol and drinking problems," Sherlock summarized, "tendencies toward violence, and severe social difficulties. Was there any promiscuity, or anything along those lines?"

She shook her head, her brows crossing. "No, of course not," she told him. "She never wanted any sort of relationship, you remember."

Idly, Sherlock considered informing her that one didn't have to want relationships to want sex. He decided against it without much thought.

"It's just… everything else. Thalia was troubled. Very troubled."

"I see," he said. "Did he behavior eventually stop?"

"Yes, thankfully, in college," she told him with a smile. Her muscles seemed to relax, as if she was glad to be done with the previous conversation. "I'm not sure why or how, but as soon as she moved off to the university, Dr. Lawrence said that she turned it off like a light switch and just thrived. Her grades weren't as good as they were in high school, but college is much harder, of course, so it's all understandable. She seems perfectly fine these days."

Sherlock almost asked, How much does she tell you? but thought better of it and revised it. "Does she stay in touch a lot?"

"For her, yes," she said. "She's never been talkative, but she visits every now and then, and we'll talk on the telephone."

"She's, I think, 29 years old, now, right?"

"Yes."

He nodded. "Have there been any relapses in the past ten years? Any odd occurrences?" he asked, playing up the "check-up" act.

"Not… really," she said, then frowned. "I don't think so, anyways. She stopped seeing her last psychiatrist, Dr. Lawrence, you know, when she graduated college."

"Right," he said, and nodded. "Has she ever asked for any peculiar gifts for her birthday, or for Christmas?"

"Well, she asked for some special knife one year, and then an expensive sort of switchblade the next," she conceded. "But living in London, I can certainly understand why. It's so dangerous up there. So, really, I don't suppose those are too peculiar."

"Hm." He nodded, and then took a final sip of his tea. "Well, I'd better be on my way - I've got two more patients to check up on this afternoon. Er, before I go, though - her files don't list her current address in London. Do you mind if I have that for the records?"

"Yes, of course," she said, smiling. She stood as he did. "She's in the Berkeley Hotel, in Belgravia. Room… hmm… I think it's room 227. Yes, that's it."

Sherlock nodded and wrote it down before putting the paper and pen away. "Thank you for your time, Mrs. Ross. It was a pleasure to meet you. I'll just see myself out." He flashed her a smile and left as she thanked him in return.

He made his way back through Guildford, and caught a bus back to London. He let his mind drift to other things, deciding he would need a nicotine patch before he would process each bit of information gleaned, and before he chose a course of action to take to finally catch this assassin.

Thalia. He rolled the name around in his head for a moment, then shook away the thought and wondered what he and John would do for dinner that night.