In which Ophelia Jane Worthington-Whittard discovers a boy in a locked room and is consequently asked to save the world

Ophelia did not consider herself brave. She wasn't like Lucy Coutts, the head girl in her grade, who once rescued a baby in a runaway stroller and was on the front page of all the papers. Lucy Coutts had heavy brown hair and pink cheeks, and she called Ophelia Scrap, which made everyone laugh, even Ophelia, to show she didn't mind.

Ophelia didn't consider herself brave, but she was very curious.

She was exactly the kind of girl who couldn't walk past a golden keyhole without looking inside.

The keyhole was in a foreign city where it always snowed. It was on the third floor of the museum, in the 303rd room. Ophelia wasn't at all sure how she got there, only that she let her feet take her wherever they wanted to go.

Her father had taken a job at the museum. He had become, at the eleventh hour, the curator of Battle: The Greatest Exhibition of Swords in the History of the World. The previous curator had left without warning. In three days, Ophelia's father was to prepare hundreds of swords to be exhibited on Christmas Eve.

He also hoped that a week in a foreign city would be just the medicine for his daughters. They could explore and ice-skate while he worked. And they would have a white Christmas away from their home, which had grown so quiet.

He was very busy, though, far too busy to spend much time with them. He told Ophelia she must stay close to her older sister, Alice. But Alice was not interested in seeing any of the attractions. She wanted to go nowhere and do nothing. She wanted to sit all day with her headphones, playing gloomy music and thinking gloomy thoughts. She'd been like that ever since their mother died, which was exactly three months, seven days, and nine hours ago.

"I'll take you ice-skating later," Alice said, but in a very halfhearted way.

So, all morning Ophelia had walked alone. She had been upstairs and down. She had climbed in and out of elevators that rattled and creaked between the floors. There were grand galleries filled with priceless treasures and glittering halls filled with dazzling relics. There were precious paintings by the old masters and glorious statues and huge urns, and the ceilings danced with painted angels. Ophelia tried, as hard as she could, to be interested in all these things.

She leaned her head to one side and nodded approvingly.

She looked up interesting facts in the rather useless guide.

She tried to stifle all her yawns.

But fortunately, these glimmering places also led to murky corridors. And these murky corridors also led to dimly lit rooms. And these rooms contained smaller, stranger collections. And it was these places that made Ophelia's heart beat faster.

She found a lonely room filled with teaspoons.

Which led to a room containing only telephones.

Which led to a shadowy arcade of mirrors.

She passed through an exhibition of stuffed and preserved elephants. She tiptoed through a quiet pavilion filled with the threadbare taxidermied bodies of wolves. She squeezed through the crowd in the Gallery of Time and saw the famous Wintertide Clock. It ticked so loudly that people had to stick their fingers in their ears. She ran down a long, dim hallway filled with melancholy paintings of girls.

It was very cold. Windows were left open to stinging sparks of sleet and snow. The wind whistled and moaned through the galleries and down the stairwells. It made the cobwebs on the chandeliers dance.

Even with a map it was a very confusing place. Signs pointed in the wrong directions, and no one bothered about fixing them. The sign for Porcelains 1700-1850 AD led to Costumes and Culture of the Renaissance. The sign for Costumes and Culture of the Renaissance led to Bronze Age Artifacts. The sign for Bronze Age Artifacts led to an imposing red, locked door.

There was no point in asking the guards. The guards sat in corners and knitted or dozed. Sometimes, they snarled and yelled like banshees for no good reason, and other times, they let children climb on the glass cabinets, using the brass handles for footholds. Sometimes, they came rushing at people who just happened to stand too long in one place, and other times, they smiled huge toothless smiles and offered old fruit from their large black handbags.

The museum in the city where it always snowed was the type of place where a person could very easily get lost. Miss Kaminski, the museum curator, had said so herself. Miss Kaminski was dazzlingly beautiful. Her blond hair was tied in an elegant chignon, and she was surrounded by a cloud of heavenly perfume. She had smiled at Ophelia and Alice before placing a perfectly manicured hand on their father's arm.

"It is advisable that they do not wander alone," Miss Kaminski said. "The museum is very big, and several girls have become lost and never been found."

But Ophelia didn't feel afraid. It was much better on her own. It was a relief to be out of the workroom, where her father had begun work as soon as they arrived in the city. He was unpacking swords and polishing swords and cataloging swords endlessly. Her father knew everything there was to know about swords. His card read:

MALCOLM WHITTARD

LEADING INTERNATIONAL EXPERT ON SWORDS

"I have a very tight deadline, Ophelia. Christmas Eve!" he said whenever Ophelia tried to talk to him. "I'm sure there are more than enough things here to keep you and Alice occupied."

If ever you have the chance to visit this museum, the keyhole to room 303 is quite close to a much-celebrated sea monster mosaic floor. It is marked on the maps by an octopus symbol. That first morning, Ophelia spent some time walking on the mosaic waves and the mosaic foam. She traveled the length of all eight glittering tentacles, observed the people falling back from the monster's mouth. She bent over and looked directly into its eye.

It was the sort of thing her mother would have loved. Ophelia Jane Worthington-Whittard wished more than anything that her mother were alive.

Near the sea monster mosaic floor, she noticed a gallery with a red rope hung across its entrance. Ophelia slipped under the rope and went inside. It was a small exhibition of broken stone angels. There was no guard in the room, so she touched some wings, even though she knew she shouldn't have. It was very quiet and very still. All she could hear were her own footsteps and her own breathing. It had a peculiar, empty smell. No one had been that way for a very long time.

In the corner of the room there was a very normal-looking gray door. Above the door were the small silver numbers 302. Ophelia opened it.

The room behind the ordinary gray door was also almost normal. The floor was checkerboard. The tall windows, with tatty velvet curtains pulled back, gave a view of the city. The sky also was gray.