The only disadvantage was that we were miles away from the kitchen, I noted as I gloomily climbed the stairs. I should have grabbed myself an apple to bring up. I’d have to make do with butter cookies from the stock Mum kept in reserve on our floor.

I was so afraid the dizzy feeling would come back that I stuffed eleven cookies into my mouth, one after another. Then I took off my shoes and my jacket, sat down on the sewing room sofa, and stretched out flat on my back.

It had been such a strange day. I mean, even stranger than usual.

It was only two o’clock. At least another two and a half hours before I could call Lesley and tell her all about it. My brother and sister wouldn’t be home from school until four, and Mum worked until five. Normally I loved being alone on our floor of the house. I could take a bath in peace without anyone knocking on the door, desperate to go to the loo. I could turn up the music and sing along at the top of my voice without anyone laughing. And I could watch what I liked on TV without anyone whining, “But it’s going to be Sponge Bob in a minute.”

But I didn’t feel like doing any of that today. I didn’t even feel like taking a little nap. Far from it. The sofa, which was usually a sanctuary, felt like a wobbly raft on a torrential river. I was afraid I might be washed away on it the moment I closed my eyes.

Trying to turn my mind to something else, I stood up and began tidying the sewing room a bit. It was kind of our own, unofficial living room, because luckily neither the aunts nor my grandmother ever came up to the third floor. There wasn’t a sewing machine here either, but there was a narrow flight of steps leading up to the roof. These were originally meant for a chimney sweep, but now it was Lesley and I who used them. The roof was one of our favorite places.

Of course it was a little risky, because there was no balustrade, just a decorative knee-high galvanized iron border along the ledge, but you didn’t actually have to practice long jump up there, or dance all the way to the edge of the drop. The key to the door was kept in a rose-patterned sugar bowl. No one in my family knew that I knew its hiding place, or you can bet all hell would have broken loose. That was why I always made sure no one saw me sneaking up to the roof. You could sunbathe there, or simply hide away if you wanted to be left in peace. Which, like I said, I often did want, only not just this minute.

I folded our blankets neatly, swept cookie crumbs off the sofa, plumped up the cushions, and put a set of chessmen scattered about the place back into their box. I even watered the azalea standing in a pot on the bureau in the corner and wiped down the coffee table with a damp cloth. Then I looked around the now spotlessly tidy room, wondering what to do next. Just ten minutes had passed, and I wanted company even more than before.

Was Charlotte having a dizzy spell again down in the music room? What actually happened if you traveled from the first floor of a house in twenty-first century Mayfair to the Mayfair of, let’s say, the fifteenth century, when there weren’t any houses here yet, or only very few? Did you arrive in midair and drop to the ground from a height of twenty feet or so? Maybe landing on top of an anthill? Poor Charlotte. But I supposed they could be teaching her to fly in her secret instruction in the mysteries, so maybe she wouldn’t end up with ants in her pants.

Speaking of mysteries, I suddenly thought of something to take my mind off it all. I went into Mum’s room and looked down at the street. Yes, the man in black was still down there outside number 18. I could see his legs and part of his trench coat. The distance three floors down had never seemed so great. I tried working out how far it was from here to the ground.

Could you actually survive a fall from so far up? Well, maybe, if you were lucky and landed in the middle of a marsh. Apparently all London had once been marshland, or that’s what Mrs. Counter, our geography teacher, said. A marsh was okay—at least you’d have a soft landing. But only to drown horribly in mud.

I swallowed. I didn’t like the turn my own thoughts were taking.

I really, really didn’t want to be on my own any longer, so I decided to pay a visit to my family down in the music room, even if I risked being sent straight out again because there were top-secret discussions going on.

* * *

WHEN I WENT IN, Great-aunt Maddy was sitting in her favorite armchair by the window, and Charlotte was standing near the other window with her hands flat on the Louis Quatorze desk, although we weren’t supposed to touch its colorfully lacquered and gilded surface with any part of the body at all. (How anything as hideous as that desk could be as valuable as Lady Arista always said I didn’t know. It didn’t even have any secret drawers. Lesley and I had checked that out years ago.) Charlotte had gotten changed, and instead of her school uniform, she was wearing a dress that looked like a cross between a nightie, a dressing gown, and a nun’s habit.

“I’m still here,” she said. “As you can see.”

“Well … well, that’s nice,” I said, trying not to stare at her dress with a noticeable expression of horror.

“This is intolerable,” said Aunt Glenda, who was pacing up and down between the windows. Like Charlotte, she was tall and slender and had bright red, curly hair. My mum had the same curly hair, and my grandmother’s hair had once been red too. Caroline and Nick had inherited the red hair as well, leaving me as the only one with dark, straight hair like my father’s.

I used to long for red hair, but Lesley had convinced me that my black hair was a striking contrast to my blue eyes and fair skin. Lesley also managed to persuade me that the little crescent-shaped birthmark on my temple—the one Aunt Glenda always called my “funny little banana”—was intriguingly mysterious and chic. These days I thought I looked quite pretty, especially now that I no longer had braces, which had put my front teeth back where they ought to be and stopped me looking like a rabbit. Although of course I wasn’t nearly such a “delightful vision of beguiling charm” as Charlotte, which was how James would have put it. Ha, ha. I wished he could see her in that shapeless sack of a dress.

“Gwyneth, my angel, would you like a sherbet lemon?” Great-aunt Maddy patted the stool next to her chair. “Sit down here and take my mind off all this a bit. Glenda is getting on my nerves, pacing up and down like that.”

“You have no idea of a mother’s feelings, Maddy,” said Aunt Glenda.

“No, I don’t suppose I do,” sighed Great-aunt Maddy. Maddy was a plump little person with cheerful, blue, childlike eyes and hair dyed golden blond. There was often a forgotten roller left in it.

“Where’s Lady Arista?” I asked, taking a sherbet lemon.

“Next door on the phone,” said Great-aunt Maddy. “But she’s speaking softly, so I’m afraid you can’t make out a word of it. By the way, those were the last sherbet lemons. You wouldn’t by any chance have time to pop around to Selfridges and get some more, would you?”

“Of course I’ll go,” I said.

Charlotte shifted her weight from one leg to the other, and Aunt Glenda instantly spun around.

“Charlotte?”

“No, it’s nothing,” said Charlotte.

Aunt Glenda’s lips tightened.

“Shouldn’t you be waiting on the ground floor?” I asked Charlotte. “Then you wouldn’t have so far to fall.”

“Shouldn’t you just shut up when you’ve no idea what this is all about?” Charlotte snapped back.

“Really, the last thing Charlotte can do with right now is silly remarks,” said Aunt Glenda.

I was already beginning to regret coming downstairs.

“On the first occasion the gene carrier never travels back farther than a hundred and fifty years,” explained Great-aunt Maddy kindly. “This house was finished in 1781, so Charlotte is perfectly safe here in the music room. At worst she might scare a couple of ladies playing the harpsichord.”

“You bet she would, in that dress,” I said, so quietly that only my great-aunt could hear me. She giggled.

The door swung open and Lady Arista came in. As usual, she looked as if she’d swallowed a ramrod. Or several. One for each arm, one for each leg, and one holding it all together in the middle. Her white hair was combed severely back from her face and pinned into a bun at the back of her neck, like a ballet teacher. The strict sort you wouldn’t want to tangle with. “There’s a driver on his way. The de Villiers family are expecting us at the Temple. Then Charlotte can be read into the chronograph the moment she returns.”

I didn’t understand a word of this.

“But suppose it doesn’t happen today after all?” asked Charlotte.

“Charlotte, darling, you’ve felt dizzy three times already,” said Aunt Glenda.

“It will happen sooner or later,” said Lady Arista. “Come along, the driver will be here any minute now.”

Aunt Glenda took Charlotte’s arm, and together with Lady Arista, they left the room. As the door closed behind them, Great-aunt Maddy and I looked at each other.

“Some people might think a person was invisible, don’t you agree?” said Great-aunt Maddy. “At least a good-bye or hello now and then would be nice. Or something really clever, like Dear Maddy, did you by any chance have one of those visions of yours that might help us?”

“And did you?”

“No,” said Great-aunt Maddy. “Thank God, I didn’t. I’m always ravenously hungry after those visions, and I need to lose weight as it is.” She patted her middle.

“Who are these de Villiers people?” I asked.

“A bunch of arrogant show-offs, if you ask me,” said Great-aunt Maddy. “All of them lawyers and bankers. They own the de Villiers private bank in the city. That’s where we have our accounts.”

That didn’t sound particularly mystical.

“So what do they have to do with Charlotte?”

“Well, let’s say they have problems like ours.”

“Meaning what?” Did they have to live under the same roof as a tyrannical grandmother, a frightful aunt, and a cousin who thought herself something special?

“The time-travel gene,” said Great-aunt Maddy. “It’s passed down through the male line in the de Villiers family.”

“You mean they have a Charlotte as well?”

“The male counterpart. His name’s Gideon, as far as I know.”

“And he’s waiting to feel dizzy too?”

“He’s already over that part of it. He’s two years older than Charlotte.”

“So he’s been time traveling for the last two years?”

“That’s what I assume.”

I tried to reconcile this new information with the little I already knew. But since Great-aunt Maddy was being so talkative today I allowed myself only a couple of seconds for that. “And what’s a chroni … a chrono-thingummy?”

“Chronograph.” Great-aunt Maddy rolled her round blue eyes. “It’s a kind of apparatus that can be used to send the gene carriers—only them, no one else!—back to a specific time. It’s something to do with blood.”