Sherlock and l got out of the taxi, which had pulled up to a tall, impressive facility. The building was pure white, but the windows were made out of darkened glass, so it was impossible to see inside. In order to get to the building, we would have to pass through several security checkpoints.

Sherlock slipped the fare to the cabby, his face drawn and seeming even paler than usual. He hadn't said a word to me on the drive over, and l had no idea what we were doing, or even where we were.

"Come on." He told me, setting down the long, narrow path to the building. "I'll explain everything inside." As usual, he answered to my thoughts, not to what l had actually said.

At each security checkpoint, he merely flashed some sort of ID card, and we were waved through. As we kept walking, l noticed that there were more and more soldiers at each checkpoint and their weapons only got bigger and bigger. Finally, we made it to a set of double doors, which(predictably) had more soldiers in front of it.

Sherlock showed the commanding officer his card, and the soldier nodded.
"Sir, we can let you through, but your partner-" He motioned to me, "-he'll have to be searched."

"Of course." My companion nodded. "That is, if you still want to come with me, John." He arched an eyebrow, half sarcastically. He knew l was coming with him, even if l had to make it through a less . . . legitimate entrance.

"Of course." I nodded, consenting to the search. "Hold on; I have a pistol in my pocket."

I turned over my gun and let them frisk me. After patting me down and examining the contents of my pockets, l was declared 'clean', although l could not have my pistol until l left the grounds.

Sherlock and l pushed through a set of double doors, entering a large, open hallway, which was filled with scientist types and people in suits. He tugged on my sleeve and guided me down another, smaller hallway. Then we went in an elevator, and he hit the button for floor 39.

The doors slid open with a cheerful ding, and Sherlock and l stepped into . . . into . . . well, I'm not exactly sure what.

There were rows or cubicles, like any other office, but unlike most offices, there were rubix cubes with hundreds of panels, chemical experiments, and math sheets covering the desks. Two kids, a short, stocky girl and a slender, fair-haired boy were bouncing a ping-pong ball across the cubicles, each of them holding a 2 paddles.

"Sherlock!" The girl called, catching sight of my companion. "Toss us those, would you?" She gestured to 2 other ping-pong balls on the floor by Sherlock's feet, and picking them up, he said to me, "Watch this."

He tossed the balls to the girl, one at a time, and in a whir of blurring paddles, she and the boy flawlessly passed the 3 balls between each other, never missing one.

"Sherlock!"

Another cry of greeting reached our ears, and I turned to see a tall girl with long, silky black hair sitting cross-legged in a bubble of light, a book in her lap. She stood up, touching a device that wrapped around her hips like a mechanical belt. The bubble disappeared, and she walked quickly over to Sherlock, her willowy form dodging gracefully between the ping-pong balls.

The two clasped hands warmly, Sherlock smiling, actually smiling, at the teenager.

"It's good to see you." She said cordially.

"The same to you, Kelsie." He replied, finally losing the air of worry that had haunted him since his brother's call.

"Hey, is Sherlock here?"

"NO WAY! He hasn't been here in forever!"

The news of Sherlock's coming spread around the cubicles, and child after child came coming out to see if the rumors of his coming were true. By the time they had stopped coming, l counted 13 in all. Their ages varied, but the youngest seemed about 9, and the oldest 16 or 17.

It was obvious that Sherlock knew them all, and that they all knew Sherlock. Moving among them happily, he listened to the chorus of children's voices that seemed to all be talking to him at once. He seemed . . . peaceful, at rest. In fact, almost a different person.

He listened carefully to a 13-year-old boy explaining something about the simplicity of rocket science, smacked away the hands of a girl trying to pick his pockets, and picked up the littlest girl and swung her up into the air as she giggled happily.

"Sherlock." Once again, the sound of his name rang through the room, but with none of the children's mirth or cheer. Mycroft Holmes walked towards us, his face stormy and foreboding.

"You do remember why I called, correct?" The older Holmes's voice was sharp, biting. I knew he was normally harsh with his brother, but this was different. He sounded as though something very, very wrong had happened.

Sherlock put down the little girl, and turned to the older children. "You know what happened, don't you?" The girl who had been playing ping-pong nodded. "We've been informed. But there hasn't been enough evidence brought in yet to work. We were waiting for more information."

"Oh trust me, there's plenty of new evidence." Mycroft's sharp voice cut the air again. Sherlock glanced his brother over, obviously reading a lot more from his brother's mood than l could.

"Which one of your men was the traitor?" He asked suddenly, grabbing a chair from out of a cubicle. Mycroft opened his mouth to answer, but Sherlock held up a hand. " Hold on. This is going to be a rather long story, so I suggest you grab a chair." He advised the rest of us. "And John, l hope you brought your notebook. This is probably going to be a very interesting story."