John Watson set the files down on the desk and pressed the heels of his hands into his head. It'd been a long day, and it was only two 'o clock. Mary opened the door of his office and poked her head in.

"You alright, love?"

He blinked a few times before he registered what she said. "Yeah! Yes, sorry. Is the next patient here?"

"Yes. I'll send him in. Oh, and Mrs. Hudson just called. Celia Williams is having her baby and she's going to go help. She left Emily with Sherlock."

"She left Emily with Sherlock?! How is that a good idea?" John couldn't believe how calm she was, she seemed to think nothing was wrong. She smiled at his incredulity.

"She'll be fine, John, Sherlock won't leave the sofa anyway." John fell back against his chair.

"I'll send Mr Hendricks in!" She trilled as she left. Of all the wild ideas, he muttered.

Emily Watson sat on the floor of the living room setting up a tea party with her dolls and Sherlock, who was on the sofa with his laptop. She finished carefully pouring pretend tea and offered Sherlock a cup.

"Would you like some tea, Sherlock?" she said as she held a pink cup up to him.

"Yes." He took it, and stared at it. "There isn't any tea in here."

Emily looked down sheepishly. "Well, mummy says that pretend teapots aren't meant to hold real tea."

Sherlock glared at her tea set. "So why not use a real teapot?"

Her eyes lit up. "Oooh, can I?"

"May I. Yes, the teapot's on the counter, next to the kettle. Try not to get burned."

She scrambled up and ran to the kitchen.

Twelve minutes later, she had a proper tea set on the table.

"Now do you want some, Sherlock?"

"Yes."

She poured him a cup, only spilling a little, and handed it to him. With big, expectant eyes she watched him take a sip.

"Hmm," he said, "actually that's quite good."

As she smiled and skipped back to her tea set, Sherlock became quite absorbed in whatever was on his laptop.

"I have to get to Kensington Gardens," he muttered.

She looked up. "Don't you have to watch me?"

"I can watch you just as well in Kensington, can't i?"

"I should think so."

He swung his legs over the couch and stood up. "Get your coat."

They made a funny pair, the tall, dark man in his black coat and the pretty blond four year old in her pink peacoat, walking down the streets of London. Donovan gave him a funny look when he got to the crime scene but let him through. A man's head had been smashed in, apparently. Sherlock looked down at Emily to make sure she was still with him, and went to look around. Emily just waited patiently by the tape. Lestrade came up to him then and watched. After a bit he saw Emily, and hadn't registered her presence all the way before Sherlock spoke.

"What happened?"

Glancing nervously at Emily, Lestrade cleared his throat and spoke. "A kid found him this morning. He's been identified as the owner of an apartment complex near here. That's about all we know, we haven't found the weapon. We think it could be something the man brought with him or maybe-"

"Emily." Sherlock cut him off.

"Yes?"

"How was this man killed?"

She looked at the body for a few seconds before answering carefully.

"Well...could he have been hit with a rock?"

"Why a rock?"

"Because there are a lot of rocks here, and my friend Timothy from school slipped once and hit his head on a rock and he had to get ten stitches, and that just seems like a good way to get somebody pretty dead."

"The four year old gets it, Lestrade. Where's the rock?"

Lestrade tripped over his words trying to catch up. "Well we have been looking through rocks here, of course, but we haven't found one that could be it."

Sherlock had gone back to pacing around the body. Lestrade spoke, partly out of bewilderment and partly to fill the space. "Are, are you quite... Why is Emily here?"

A voice carried from the stream. Neither had noticed that Emily had wandered off. "Mr Lestrade! What about this one?"

Lestrade jumped. "Don't run off like that, sweetheart!"

Both men scrambled to join her in the muddy riverbank. As Sherlock bent over to examine her rock, Lestrade tried to give her a lecture.

"Sweetie, you can't run off! It's not safe out here. We've been looking at rocks all morning, what makes this one different?"

"It's the wrong kind! All the rocks by the stream are smooth, but this one is hard like the ones in the grass!" "

Emily, there are a lot of rocks here-" Sherlock held the rock out under his nose. There were spots of blood on it that the river hadn't washed off. Lestrade just stared at it, while Sherlock started talking.

"You should have tried the river first. Easy place to dump something as ordinary as a rock. It would wash away all evidence, but the murderer didn't get it all the way in the river, his throw fell a foot short, but he didn't check to make sure. Which means he was in a hurry, which means he was pursued. Someone other than the murderer knows this happened. Who is it, and is he still alive?" He'd stepped a few feet back from Lestrade while he was talking, and now he tossed the rock to him.

"His name is Henry Stockholm and he went towards Cheswick." As Sherlock started to march off, Lestrade started sputtering questions.

"But, is he dead?"

"Possibly, how am I supposed to know that?"

"How did he know that the murderer-"

"Catch him and find out. Come along, Emily."

Emily skipped to catch up to him. She had to take two steps for each of his long strides, but she kept up. Glancing up at him to make sure she had it right, she set her face to an expression she thought mirrored his and turned her coat collar up.

On the floor of the living room again, the tea set had been put away and Emily was coloring. John Watson burst into the room a little unceremoniously but stopped when he saw the scene laid out in front of him. Emily squealed when he came in, and gathered up several of her pictures.

"Daddy! Look! I drew a river!"

"That's great, sweetheart, Sherlock, what's going on?"

Sherlock didn't look up. "Well I imagine she's drawing you a picture, but you're the parent, not me, so you should know."

John made a pronounced gesture,—why me?—and stalked off to the other room.

Mary's voice came up from the hall. "Emily! How did you get this much mud on your shoes?" Emily looked up at Sherlock.

"You'd better go explain. She's your mother, not mine."

Emily got up and pranced to the hall door. Mrs Hudson called up, "Sherlock! Why is there mud all over my doorstep?"

Sherlock just sank deeper into the sofa.