By the time we pulled up to Greystone, I had a full page of notes, and I hurried to finish them as the cab stopped.

“Come on, Watson.” Holmes tossed a bill to the driver and dragged me out the door.

Greystone, it turned out, took up the top ten floors of a glass tower that loomed over the rest of the block, new and strange in its surroundings. Because it was private security—because it was Milo—we were put through a metal detector, a full-body scan, and two separate fingerprinting kiosks before we were sent up to him on the freight elevator. Floor after floor of office space. His penthouse was at the top.

“He knew that we were coming, right?” I asked Holmes for the tenth time.

“Obviously,” she said as the elevator lurched. “Did you notice how hastily that retinal scan was set up? He’s obviously watching his security feed with a bowl of popcorn. Jackass.”

The elevator lurched again.

“Stop insulting him,” I told her, “or we’re going to plunge to our deaths.”

Milo Holmes had always reminded me of an actor who’d wandered in from a movie set in another century. He had the same sonorous speech as an English professor, and I’d never seen him wear anything but a tailored suit. (One of those suits was folded up in my suitcase. I tried to feel bad about having filched it, and failed.) His offices were just like him—old-fashioned and stuffy, like the MI-5 of old spy novels. It was like he’d cherry-picked his favorite fictional references and rearranged them into a hodgepodge of mismatched places and times.

But I hadn’t really expected the armed guards.

Two steps out of the elevator, and a pair of them stopped us, automatic weapons pointed at our chests. One started mumbling rapidly into her wrist, something about unfriendlies and unauthorized access.

“We were cleared. We should be fine,” I said to the guards, my hands up. They didn’t budge. “Uh. Should I be speaking German?”

The other soldier hoisted his gun to my face.

“I guess not.” It came out sort of high-pitched.

Holmes, unbothered, was peering up into the light fixture. “Milo. I know you can hear me. Have you entirely forgotten your manners? You’re making Watson squawk.”

“Of course I haven’t,” her brother said, stepping out of a door that swung open from the wallpaper, as if invented on the spot. He nodded to his guards, and they shouldered their weapons, disappearing down the hall in the two-bit magic show that was Milo Holmes’s bread and butter.

“Wasn’t that fun?” he asked.

“No,” I said. “Do you treat all your guests this way?”

“Only my little sister,” he said, tucking his hands into his elegant pockets. “You know, you could have come up the visitors’ elevator, and we would have had far less trouble.”

“They put us on—”

Holmes lifted a hand to stop me. Her eyes were scanning the room. “You haven’t updated your lobby. It still looks like an ugly antiques shop in here.”

“It is, as you well know, not a lobby. This is my private residence,” he said. “You’ve seen the actual lobby quite often. And now you’ve been x-rayed in it. Would you like to visit it again?”

“Yes, it is so good to see you spending your time on worthwhile causes like photographing my teeth when you could, in fact, be looking for our uncle. Or adding guards to the family estate.”

“Who says I’m not?”

“I am. I’m watching you do nothing.”

“You wouldn’t know how to look.”

She took a step toward him. “You monstrous pig, I knew how to read people before you knew your alphabet—”

“Oh? Because I’ve been holding my tongue about the fact that you and your ‘colleague’ there have obviously begun doing the nasty, and that—pity—it’s not going very well—”

At that, Holmes lunged, and he dodged her, letting out a triumphant laugh.

“Guys. Guys. Where is he?”

“Who, Watson?” she asked.

“August Moriarty. The reason you two are fighting? I could be wrong about that. It’s just an assumption.” I looked Milo over, head to toe, the way I’d seen him do to me. “As is the assumption that no one’s done the nasty to you in years. Three? Four?”

Milo adjusted his glasses. Then he pulled them off and began polishing them with a sleeve.

“Two, actually,” a soft voice said behind me. “He never really did get over that comtesse, and I haven’t seen any girls around here since.”

Charlotte Holmes went completely still.

“Though it’s been longer for me,” the voice said. “So I shouldn’t really be making fun. Speaking of, I hear I have you three to thank for breaking off my engagement. And I do mean that. Thank you.”

Milo sighed. “August. It’s good you’re here. Lottie, I’ve given him access to my contacts. He’ll show you around. I—well, frankly, I have more important things to do.” He stopped at the end of the hall. “By the way, Lottie, Phillipa Moriarty called to confirm your lunch. I’ve left her number in your room.”

With that bombshell, he left. I didn’t have any time to process it. I’d been left with Holmes and Moriarty. And because I was—am—a coward, I waited until the last possible second to turn around.

August Moriarty was dressed like a starving artist. He had on ripped black jeans and a black T-shirt and steel-toe boots—black, of course—and his hair was cut into a blond fauxhawk. But while he was dressed like a poet, he had the polish of a rich kid, and his eyes were burning with an intensity that reminded me of—