A/N: Thanks so much to reviewers who gave me feedback on the last few chapters! I really want to continue this project and it's great to have support in doing so. No real warnings for this chapter other than it being a bit long, sorry! Enjoy!

Moriarty went off the grid. Sherlock tried helplessly to search for him, but he couldn't seem to find any indication of the villain's whereabouts. His activity had gone fairly quiet once more. This seemed to be Moriarty's new game. Staying hidden for long intervals only to pop in and surprise them again. He was right—it wasn't unlike Sherlock's checkups.

They had their first one early one Saturday morning. Some bespectacled woman with a clipboard came through, marking things off as she walked around the flat, asking questions to Sherlock about meals and schedule and those sort of things. She asked Alex a few questions too, but he handled those well, smiling at the woman and using good manners. Sherlock did his best to keep his retorts to a minimum, though it was difficult.

"So sorry you're compensating for a loveless marriage by working yourself so hard," slipped out at one point, though thankfully it was mumbled to such an extent that he was able to rethink it by the time she asked for him to repeat what he'd said.

Thankfully, all major disasters were averted. He managed to snatch his small jar of human tongues up off the counter and hide it out of sight before she entered the kitchen. And Mrs. Hudson eased his impatience some when she brought up tea and cake.

With the inspection passed, Sherlock allowed himself to relax some. If he kept up his hard work it was obvious his guardianship wasn't going to be contested.

Of course, Mycroft's own inspection was another thing. Him showing up one day, asking to come in.

"What do you want?" Sherlock snapped.

"Just coming to see how parenthood is suiting you," Mycroft said.

"I would have thought you could check in with that appalling woman who was here a week ago," Sherlock muttered.

"Oh I have, but I know she wouldn't be quite as thorough as I will be," Mycroft said, glancing about, eyes lingering on the dinosaur toys on the floor, the crayon drawing on the fridge. "This is a change. I never thought I'd see something like this. You do know mummy won't stop pestering me about when you'll let her meet Alexander."

Sherlock said nothing. It made sense his parents would want to meet the boy, of course, but that didn't change the fact he'd much rather avoid contact with them entirely. Though, with Alex there to distract them, it might be a little more bearable.

"I see you've missed a few things though," Mycroft said. "I'd avoid leaving those knives in this room, even in a drawer if I were you, Sherlock. And your nicotine patches really should be kept in a better place as well. For goodness sake, you do realize that shoving things under the sofa does not count as cleaning. And you really ought to get a safe for your gun."

"Not when Moriarty's barging in here unannounced," Sherlock muttered.

"Yes, you mentioned that in your text. I'm afraid our efforts to track him have continued to be fruitless," Mycroft sighed.

There were footsteps on the stairs and then Alex appeared in the living room. He was holding a piece of paper over a glass.

"Sherlock, I caught a spider again. Can you show me a new way to kill it?"

Mycroft glowered at Sherlock before turning to glance over the boy, probably making his deductions. Sherlock made his own to see if there were any that might be troubling. Alex was barefoot, wearing a blue t-shirt and jeans; dust was smudged on both from where he'd probably crawled under something to find the arachnid. Tousled unbrushed hair… Mycroft might not like that, but there was a slight speckling of toothpaste under his chin that showed he'd at least cleaned his teeth earlier that morning, and a smudge of jelly on his shirt collar that showed he'd eaten.

"Trying to instill psychopathic behavior in him, Sherlock?" Mycroft said with a sigh. "Really, don't you have better things to do?"

Alex's brow furrowed much as John's might have done in the same circumstance. "Sorry, what?"

Mycroft ignored him. "I suggest you avoid such habits in the future. I highly doubt the social worker will approve if she finds out. Also, I'd suggest trying to add some balance to his next meal—and no Sherlock, ice cream does not count as a meal. And if I were you I'd pay a little more attention. Honestly, brother, your observation skills could really be improved."

He walked back towards the door. Sherlock stared at a spot on the wall, waiting until he heard the footsteps descend all the way down to turn back towards Alex. The boy was frowning as he looked at the glass.

"Maybe I'll just let it go," Alex whispered. He walked over to the window, and Sherlock heard him open it to allow the spider out.

Sherlock rose to his feet. "Let's go out."

"Where?" Alex asked.

"Just out," Sherlock muttered. "On a walk. For food. For whatever, just out of here."

Alex shrugged but went back to find his shoes and coat. Sherlock pulled on his own, turning up the collar as he glowered, thinking on what his brother had said. He was doing just fine with Alex. Psychopathic tendencies indeed. Killing the spiders was an experiment. They were quick spawning arthropods, not cat or dogs or something of the like. It was merely an amusing activity Alex seemed to enjoy. He'd showed no other signs of even being a sociopath like Sherlock was. He was a sweet and loving boy; he did well in school and made friends with few problems. And what on earth could Mycroft mean about his observation skills?

When the boy came charging back down the steps, Sherlock tried another deducing glance. He'd been painting earlier today, clearly. He had been in a fight at school two days ago…but they'd had a talk about that at the time. There had been another small growth spurt in the last month, evidenced by his slightly too short coat sleeves. He'd snuck a few sweets earlier, but that again didn't concern Sherlock very much. What was he missing? Perhaps Mycroft has simply been taunting him.

They headed off down the stairs. Alex poked his head in Mrs. Hudson's door and told her they were going out, asking her how she was doing before bidding her a good morning. When the boy was finally done being social, they headed off down the street, pausing only a few blocks away when they reached a small café.

"Hungry?"

Alex nodded eagerly and dashed in without giving Sherlock another chance to reconsider. The detective sighed before following after him.

They sat at the table. Alex beamed at the waiter and ordered the same thing he always did. Sherlock snorted and asked for a drink instead, deciding he wasn't particularly hungry. The waiter chuckled at Alex's enthusiasm.

"And how old are you, young man?" he asked.

"Six," Alex said with a grin.

"Ah, a fine age! Well, will that be everything, sir?"

Sherlock nodded, only to sit up straighter, glancing at Alex with eyebrows furrowed.

"Hold on a moment, you're…six?"

"Yep," Alex said with a shrug, staring down at the table and tracing his finger over a crack in the surface. Sherlock stared at him a moment longer, trying to process.

"You…you had a birthday," he stated.

"Yes," Alex agreed. "It's March thirteenth."

That was more than a week ago. Sherlock blinked a few times.

"Your birthday passed and you said…nothing?"

"It wasn't that big of a deal," Alex said with a shrug. "I…I made you build me a blanket fort again. And I made you go get ice cream for dinner. That was enough for me. I thought…I thought if we actually celebrated it'd just make me think of mum and dad."

Sherlock wondered at how he'd come so far as to not feel panicked on sight of tears in those blue eyes.

"Well, is there anything else you'd like to do," Sherlock asked, willing back the lump in his throat at the thought of having to throw a party or something of the like.

Alex brightened some. "You mean it? Well…there is one thing."

Sherlock arched an eyebrow. "Yes?"

Please don't let him say party, please don't let him say party Sherlock clamped his teeth down hard in an effort to keep the words from escaping his mouth. Perhaps he shouldn't have made such an offer. Oh this was foolish. Six year olds running about the flat in celebration—he could picture it already.

"I want to come with you to another crime scene," Alex said.

Sherlock's breath spewed out in relief. However, as he finally began to think about what Alex had just said, he realized it wasn't altogether better.

"I'm not allowed. Lestrade would have my head."

Alex let out a giggle and grinned. "Please, Sherlock. Why not?"

"Because of those silly rule things," Sherlock sighed. "Anything else?"

"That's it," Alex said. He shrugged and looked at the table, though thankfully the waiter came back with his food just in time to distract him.

Sherlock sipped at his drink and considered.

Later that day he made a call to Molly Hooper. She answered excitedly, her tone causing Sherlock to roll his eyes. Obviously the latest boyfriend hadn't quite panned out.

"I need your help," he said. "Alex wants to go to a crime scene for his birthday, but Lestrade won't let me bring him anymore. I was thinking the morgue might be the next best thing. Would you allow him there?"

"Are you joking? Sherlock, he's only five!"

"Six," Sherlock said. "I missed his birthday…hence why I'm trying to make up for it and take him somewhere special."

"Oh golly. Hmm…I think I can help. But you'll have to do exactly as I say."

"Fine," Sherlock muttered, though he wasn't sure if he entirely approved. Nonetheless, he agreed to have her over the next weekend. She hung up saying she had lots to do, not comforting him one bit.

A week later Molly arrived dressed in her lab coat and asked him to come help her carry things from the cab. Sherlock was a bit surprised but agreed, sending Alex down to Mrs. Hudson's for a bit while he helped Molly grab numerous bags and boxes, coming back up to the flat with an armload of various things.

As soon as they had managed to unload everything, Molly shooed him away and set to work. Sherlock had never seen her more frantic, rushing to set everything right. Unsure how to even begin to help, Sherlock managed to get out of her way, watching and attempting deductions on what she could possibly be planning.

There was a knock on the door. Molly turned a pointed stare at him and ordered him to get it. He trudged back down the stairs to find Harry Watson standing in the doorway an attractive woman standing behind her.

"You forgot my nephew's birthday," she said with an eye roll, stepping into the hallway and pushing past him.

"So did you," Sherlock pointed out.

"Not my kid, not my responsibility," she said with a half-smile. "Oh, Anna darling, this is Sherlock Holmes, my brother's best friend and Alex's guardian now."

"The Sherlock Holmes?" Anna asked, glancing between the two of them with wide eyes.

Sherlock looked her over, taking in the ink smudge on her wrist and the chalk dust on her skirt. Teacher. The necklace she was wearing had a small A and H engraved on it, serious then. The jewelry appeared to have been worn regularly, but did indicate a certain level of care. Things were going well then. Anna smiled warmly at him and though he didn't particularly like it, he had to admit it seemed Harry had chosen a fitting partner.

"Well, why don't you let us go see if er…Molly wasn't it? Yes, if Molly needs our help."

She headed towards the stairs, Sherlock noticed the bags in her hand as well. Whatever was apparently bigger than he'd anticipated. Sherlock felt his stomach sinking. Especially when he noticed someone else coming to the door.

"What are you doing here?" he asked Lestrade.

"Got some kind of an invite from Molly," the man said with a shrug. "Figured I'd come over. It's the little tyke's birthday, isn't it?"

"Yes," Sherlock said, glancing at the wrapped gift in Lestrade's hand as well. Trust Molly to blow things out of proportion this way. "Yes it is. Do you know of anyone else coming?"

"Eh, when I asked her she mentioned you, Mrs. Hudson, John's sis and that's it. I think it'll be fairly small."

Sherlock let out a dramatic sigh and shut the door, following Lestrade up to the flat only to find that Molly had completely rearranged everything. On the floor was a dummy, arranged at an odd angle. To the side was a fake gun and several pieces of furniture appeared to have been knocked over. Molly was standing there looking very proud of herself.

"Alright you lot, I need your help too. Please take these and look them over." Molly passed around cards.

Sherlock glanced at his, taking in a profile that fit him in terms of description, other than describing him as a musician with two children and a wife. He had been to dinner with a friend from 6-8 before going home to his family that evening. He had been known for his temper, had more than one incidence of violence in public, and had been seen with the victim on the day of his death. Getting a general gist, Sherlock began to realize Molly had apparently set up some kind of murder mystery. Wonderful.

"That, is Anthony Rosenberg, the director of the Royal Opera House," Molly began, stuttering a bit in her nervousness. "At approximately 7:13 AM this morning, he was discovered in his own private rental flat by the landlady. The case has baffled police who've decided to call in an outside detective to make sense of it. He will examine the crime scene and do a few interviews with the main suspects. We have the angry musician who worked in the opera house," she glanced at Sherlock. "We have his wife, who was getting ready for a divorce," she looked at Anna who giggled. "His son who will inherit everything," she glanced at Greg. "His supposed mistress," she said, glancing at Harriet. "And of course, his housekeeper who will be letting the detective up in just a moment."

Sherlock sighed and rolled his eyes, but he supposed this was more efficient than letting Alex at an actual crime scene.

Mrs. Hudson came up the stairs with Alex. Sherlock turned to see the boy with one of this silly hats on, vibrating with excitement. Molly smiled and walked over crouching down to explain things to Alex. The boy nodded eagerly, accepting her offer to help him with some of the trickier aspects.

The guests stood to the side while Alex examined the body. He made remarks to Molly, plucked up a hair from the man's jacket as evidence, and dusted for fingerprints. Molly promised to set to work on lab analysis for him, even as Alex began to start interrogating the suspects. Sherlock already knew who it was, and it was tempting to just tell the boy and have it over with. Even so he allowed Alex to come over and start talking with him.

"Where were you on the night of Mr. Rosenberg's murder?" Alex asked.

"I was at dinner and then home with my wife," Sherlock answered.

Alex glanced down at the cards. "Your wife says you weren't home from dinner until after eleven, but the restaurant saw you leave at eight."

Sherlock sighed. "Well, I went for a walk afterwards."

"But you have no alibi for that time?"

Sherlock shook his head and sighed.

Alex went around and asked the same questions amongst the rest of the group. Sherlock waited until Molly returned with the "lab results" telling Alex that the DNA and fingerprints both matched Sherlock's character. Alex looked at the information himself before turning to look at Sherlock.

"I'm afraid the evidence seems to point to you," Alex said with a sigh. "Any detective would declare you guilty. But I'm not just any detective." He grinned and tugged at his cap and Sherlock did feel a minimal bit of pride at the boy's ability to see past the obvious.

"Your fingerprints and hair are on him because you did see him that night in this flat where you've been seen before. There are fingerprints under his shirt too, but none on his buttons so you didn't undo it or redo it. Clearly he or someone else put his shirt back on prior to his killing before the weapon pierced his chest. You are too embarrassed to say why and know it will make you look guiltier," Alex said. "You're…um…" he looked at Molly who nodded. "You're lovers."

There was a small gasp around the room. Lestrade chuckled and winked at him even as Harry raised a brow.

"Yes," Sherlock said. "Precisely. Now, if it's not me why don't you tell us all who it is?"

"Well, the person who was there after you left of course," Alex turned. "Out of habit, after you two are finished Mr. Rosenberg will have the place cleaned by his housekeeper. And it's obvious too because some of the dust had been swept off the mantle, but the rest of the place was fairly dirty, showing she'd started her job but not finished. She was interrupted."

"But why would a kind old housekeeper kill Mr. Rosenberg?" Sherlock pressed.

Alex tilted his head. "Well, the logs say she had a call from a burner cell prior to committing the act. So I'd say she was being paid by someone."

"Good. And that person is?"

"Well obviously who is the person who cares the most about him having an affair and has the housekeeper's number? Well that would have to be the other person who hires her, Mrs. Rosenberg," Alex said grinning from ear to ear.

"Oh you've got me," Anna said with a dramatic sigh. "You've figured out my dark plan."

"So, you and Mrs. Hudson are both under arrest," Alex said with a giggle.

"Oh you did so well, Alex!" Molly said, coming over to give him a big hug. "Look at you, such a smart little detective."

He smiled and leaned into her embrace before being interrupted by Mrs. Hudson.

"Oh isn't that perfect, but we do still have cake and presents too."

Alex smiled and agreed, asking the other guests to come downstairs to eat whatever Mrs. Hudson had made. They followed her to the stairs while Alex came back over to Sherlock.

"Did I do well?" he asked.

"You were spectacular," Sherlock said, even though he believed he could have solved it much faster at Alex's age, it was still impressively done. "You make a fine detective."

"Thanks," Alex said. "But obviously you're the best. There isn't a crime you can't solve!"

Sherlock just gave a small chuckle and led Alex towards the rest of the party. He couldn't help but think about how he still hadn't been able to find Moriarty. Alex's assessment seemed a little poor in light of that fact, but the detective decided to not spoil the day, leaving Alex to his joyous smiles as he awaited cake and ice cream.