Two hours later, in an opulent palace far away, a hall full of glass came to gleaming life. Hundreds of candles flickered in massive crystal chandeliers that hung suspended on long cables from a painted ceiling far above. Down one wall hung a bank of well-polished mirrors that were famous around the world. Down the other wall, tall windows reflected the light dim yellow back inside. Outside it was the dead of night. No one near the Palace of Versailles noticed the unusual light flickering inside, or the people it illuminated.

Meanwhile, in Portland, Jack and Jaide were in the blue room, peering into a much less elaborate mirror. This mirror was lying on its side and resting on two chairs, whose backs supported its heavy weight without complaint. The mirror, which normally reflected images in a perfectly ordinary fashion, now acted as a window to the famous Hall of Mirrors, where they could see Wardens from all over the world assembling for the historic Grand Gathering of the Glass.

Grandma X was pacing on the other side of the blue room, out of the mirror’s sight, one hand pressing on the pocket where the note still sat. She had revealed nothing more since the discovery of the cross-continuum conduit constructor, but she was muttering silently to herself, which was in itself more worrying than anything she could have said. Jaide and Jack waited with impatience for the Gathering to begin in the hope that they would learn what on earth was going on.

Perched silently in her cage, Cornelia watched closely with one black eye, taking in everything and saying nothing.

“Were you at the last Grand Gathering?” Jack asked Custer, a local Warden who was watching with them in the blue room. He was a middle-aged but somehow ageless man with high cheekbones and long blond hair. His most striking feature was the ability to turn into a saber-toothed tiger at will. He had tried to teach the twins to shape-shift, but neither seemed to possess Gifts that worked that way. Everyone assured them that they would have other Gifts, possibly soon, but there was no way to tell what they would be. It was just a matter of waiting to see.

“I was present at the last Grand Gathering,” Custer replied with a formal inclination of his head. “It is good that such terrible times are long behind us.”

Grandma X shot him a look that Jack couldn’t interpret. Perhaps she was warning Custer not to give away too much. There were supposed to be no secrets between her and the troubletwisters anymore, not after the last time The Evil had attacked, exploiting knowledge that had been kept from them, supposedly for their own good. That the twins were present for the Grand Gathering suggested that this compact was being honored, but they knew there were limits nonetheless. They were troubletwisters and they were kids. It didn’t come easily to grown-up Wardens to treat them like equals.

“Look, there’s Dad!”

Jaide had spotted Hector Shield in a reflection of a reflection. He was peering out of another mirror, just as floppy-haired and crumpled as he usually looked. His glasses sat on a slight angle, and she wished Susan, her mother, was there to straighten them for him. Susan wasn’t a Warden, but like Tara and Kyle she was aware of the twins’ training. It was her job, she said, to make sure everyone remembered there was an ordinary world out there, too, full of things like homework and chores. She was an aero-ambulance paramedic who worked three-day shifts outside of Portland, and although the twins missed her, it also meant she was usually away when they were exercising their Gifts. It worked better that way.

Hector waved, waggling all ten fingers of both hands and beaming in welcome, but it was impossible to talk to him. A loud buzz of voices issued from the mirror as Wardens from all over the world joined the vast assembly through mirrors of every shape and size. Faces peered out of bedrooms, closed shopping malls, dressing rooms, and airports. Every age, race, and culture was represented. Some of the Wardens had clearly been woken from deep sleeps to attend and were still in their pajamas. One appeared to be underwater, peering into the reflection of her goggles. All of them were adults. Look though he might, Jack saw no other troubletwisters.

Sometimes Jaide could make out fragments of what they were saying to one another. It seemed to be variations on a single question: What’s going on?

An imposing figure stepped into the Hall of Mirrors, a man wearing a dark gray suit, with broad shoulders and a full, bearded face. His hair was yellow and thick, and stood out like a mane. The twins had never seen him change shape, but nothing would have surprised them less than learning that he could turn into a lion.

His name, they knew, was Aleksandr, and the few times they had met him he had seemed to be in charge, as he appeared to be now. With ringing footsteps, he walked down the gallery to its center and stood there alone, staring at the mirrors surrounding him.

When silence didn’t fall immediately, Aleksandr raised his left hand and snapped his fingers.

Jack and Jaide held their breaths. There was suddenly no sound at all. It was as though the air in the blue room had vanished, replaced by a feeling of great significance — of history, even.

“The Warden of Last Resort calls us,” Aleksandr said, “and we have come, the Grand Gathering of the Wardens of Earth, only summoned in times of direst need. We await the reason for our summoning.”

He paused, and his deep voice echoed off marble and glass, rolling and rumbling for a full second.

“It had better be good,” Aleksandr added before the last of the echoes had faded away.

Before Jack could ask Custer who the Warden of Last Resort was, a clear strong voice spoke out in reply.

“She’s alive,” said Grandma X.

Jaide jumped several inches in the air. She hadn’t noticed her grandmother coming up behind her. Grandma X put her right hand on Jaide’s shoulder, pressing her back into her seat. In her other hand she held up the note.

“Who is alive?” asked Aleksandr.

“My sister.”

“Impossible.”

“I have proof!” said Grandma X over a rising hubbub. She tried to explain about what the twins had found, but too many voices shouted her down. Aleksandr raised his hands for calm, but even he couldn’t bring order. All he could do was wait until everyone’s surprise and shock — and no little outrage, it seemed — had been vented.

“The message was from Lottie?” Jack asked Grandma X in a whisper, while he had the chance. He and Jaide had been hunting for information about their missing great-aunt, Grandma X’s twin, for months now, and had turned up nothing except that she’d disappeared long before they were born. They had assumed her dead at the hand of The Evil, but they had never been able to prove it. It was incredible that news of her had turned up like this.

If the note had been written by Lottie, and had come from the same place as The Evil, that meant Lottie was in the Evil Dimension. They had received the merest glimpse of that place the day their Gifts had woken, and it had been horrible. To be trapped there … Jaide shuddered at the thought, and Jack hugged himself.

Grandma X glanced down at the troubletwisters. She had heard Jack’s question, but for a moment she didn’t seem to see her grandchildren. Her gray eyes were full of grief and anger. This wasn’t a secret that had been kept from them, Jack understood. No one had known, not even Lottie’s own twin sister.

Grandma X sighed, nodded, and seemed to grow suddenly impatient with the racket. When she spoke again, her voice was like thunder, and it drowned out anyone who tried to speak over her, even Aleksandr.

“My sister is alive,” she said, “and you know what that means.”

The twins didn’t know. They waited breathlessly for silence to fall, in hope and dread of finding out.

“We abandoned her,” Grandma X said in her ordinary voice. Custer reached up to take her hand but she shook him off. “We left her to die, all of us, even me — but she didn’t die. She has endured horrors we cannot imagine. Yet she lived in hope all these years. She sent us a message, and she waited and waited for rescue, and we didn’t come. She is still waiting for us, even now, after all we have not done for her.”

“She might be dead —” said Aleksandr.

“She is not. The living-mail charm dies with the user.”

“Then it is a trap, set by The Evil to sow dissent among us.”

“She would never fall.”

“How can you say that? No one is entirely immune here, let alone there, where The Evil’s power is strongest.”

“Lottie would die first,” said Grandma X. “I was the weak one, not her.”

Jack was horrified to hear his own fears coming from his powerful, confident grandmother’s mouth. The Evil often claimed that of every set of troubletwister twins one would turn to its side. Their father’s twin brother, Harold, had done exactly that, and there had been moments when The Evil’s power had been almost too strong for either Jack or Jaide to resist. Each time, they had been saved, but maybe it was a matter of time, and when their time ran out, the weaker would fall.

If Grandma X was the weak one, thought Jaide, how strong must Lottie have been?

“We must rescue her,” said an elderly Warden from the far end of the Grand Gathering. “Lottie and any others who remain with her.”

“We cannot,” said Aleksandr.

“It must be possible,” said a Warden peering through a shaving mirror. “By what means was the message received?”

Grandma X briefly explained about the discovery in the grounds next door.

“The artifact lay dormant until exposed by happenstance,” she concluded. “The presence of the troubletwisters activated it, and a Bridge briefly formed.”

Jack and Jaide felt the combined attention of the Grand Gathering fall upon them, but not for long. Their role in the events of that day was a crucial but small one.

“Another Improbable Conglobulator?” said a Warden incredulously. She was one of several in a fun house, her image twisted into an impossible shape. “It surely cannot be the one Lottie herself used.”

“It must be,” said Grandma X. “Lost but not destroyed, as we thought it had been.”

“Could we use it to send someone after her?” the twisted Warden asked.

“That would be extremely dangerous,” said Aleksandr. “Any conduit to The Evil flows both ways. Was there an incursion in Portland?” he asked Grandma X.

“There was,” she said. “A small one, and it was contained.”

“Possibly because the conduit was open only long enough to allow the message through. A more significant breach, one large enough to send a whole person, might wreak a terrible toll, perhaps even destroy the wards.” He shook his head gravely. “We learned forty-five years ago what meddling with the realm of The Evil can do. This device must never be used again.”

“You would have us do nothing?” asked a Warden gazing into the reflection of a perfectly still pool.

“Lottie and her friends acted recklessly and without forethought,” said Aleksandr in a deep warning voice. “Their willfulness cost the lives of many other Wardens, Wardens who sacrificed themselves to seal the breach between Earth and the realm of The Evil that she opened. Reopening that breach will undo their valiant efforts to save this world. It will put us all at risk. And …”

Here Aleksandr hesitated. He seemed to be considering the wisdom of his words, and the twins wondered if he was about to change his mind.

“There is something I must tell you,” he said. “It will be news to most of you, because the information has been kept secret for fear of The Evil’s spies learning of it. A great work is being undertaken, even as we speak. Its existence will explain why I said that we cannot rescue Lottie, rather than will not.”

He paused for dramatic effect.

“The relic of Professor Olafsson, inventor of the cross-continuum conduit constructor, Improbable Conglobulator, Bifrost Bridge — call it what you will — has been recovered. With his knowledge and the professor’s original notebooks, we have discovered a way to neutralize the threat of The Evil once and for all. When Project Thunderclap is put into effect, the realm of The Evil will be barred from our world forever. I expect this to happen in a matter of days.”

The hubbub this announcement provoked was even louder than the first one, although this time the twins didn’t understand why. Among renewed cries of “Impossible!” Jaide heard several voices shout “Madness!” or “Insanity!” A Warden in a turban called out, “Isn’t this what led to the Catastrophe in the first place?” Those Wardens who remained silent, she assumed, were already in on the plan.

“They really found the professor?” Jack whispered to Custer.

“So it would seem.”

That at least was good news. They had discovered the animated death mask of the long-dead Warden in Rourke Castle six months ago. He had helped them and become a rather peculiar friend until he had been snapped in half and stolen by one of The Evil’s spies.

“The Hawks have clearly been busy,” Custer added.

“The who?” Jaide asked.

“There are factions among the Wardens. The Hawks advocate taking the fight to The Evil, rather than merely defending ourselves from it. The Doves want us to try to negotiate with The Evil, to arrange a peace. They have always argued. Ever since the Catastrophe, the Hawks have been in ascendance. Lottie’s actions —”

“Lottie kept her own counsel,” said Grandma X. “And she never entertained the possibility that she might be wrong.”

“Why wouldn’t we want to cut off The Evil?” asked Jaide. “Anything to make the world safe, right?”

Custer indicated the mirror, where Aleksandr had raised his hands for calm. The Gathering was settling. Hector was no longer smiling.

“I will tell you everything in a moment,” Aleksandr said. “Let me just say now that the success or failure of Project Thunderclap rests entirely on surprise. Tip our hand too early, and we will fail. Leave it too late, and the same thing will happen. Even if we succeeded in rescuing Lottie without alerting The Evil to our plans, we could not trust Lottie to keep this secret. Therefore, I ask all of you to put aside thoughts of Lottie or anyone else trapped with her. She made her choice long ago, and the weight of it must rest heavily on her shoulders alone.”

“You want us to ignore another Warden’s cry for help?” asked Hector, his expression appalled. “Once the realm of The Evil is sealed, she will be permanently out of our reach.”

“Yes.” Aleksandr’s expression was grim, but unflinching. “That is the way it must be. We have each of us taken oaths binding us to a single great duty: to save the world from The Evil. To serve that greater good, we must sacrifice our individual concerns, just as we must sometimes sacrifice ourselves.”

A new hush filled the Hall of Mirrors, one of nervous anticipation. Aleksandr was talking to Hector, but all knew to whom he was really addressing his words. The twins looked up at Grandma X and could tell by the clenched muscles in her jaw that she knew best of all.

“Will you promise me,” Aleksandr asked her, “not to attempt a rescue?”

Everyone’s attention was on Grandma X, who stood stiff-backed and silent in the face of their combined regard. The twins waited for her to speak, knowing that she would never agree to such a terrible thing. Jaide tried to imagine what it would be like if Jack was the one in the realm of The Evil. She would stop at nothing to get him back, no matter what he had done. Jack felt exactly the same way. They were twins. They were troubletwisters. It was hardwired into them to help each other in times of serious need.

There wasn’t a person in the Grand Gathering not feeling that way, they were sure. So why would Aleksandr ask the impossible? Grandma X couldn’t possibly agree.

“Promise me,” he said again, and this time it was an order, not a request.

Jaide could practically hear her grandmother’s teeth grinding.

“Yes,” she finally said. “I will do as you ask.”

The twins were aghast.

“You can’t!” blurted out Jaide.

“But she’ll die!” said Jack.

“Lottie has been dead to those who loved her for many years,” Aleksandr said.

“So?” said Jaide. “This is wrong, and you know it. You’re wrong to ask Grandma to do this.”

“There must be another way,” said Jack. “We have to help Lottie get back.”

“Silence!” ordered Aleksandr.

“Hush, troubletwisters,” their grandmother said.

The light flickered in the blue room. A gust of wind sent Custer’s long hair dancing.

“How would you feel if your twin was stuck in the Evil Dimension,” Jack asked Aleksandr.

“Or you,” added Jaide. “What did Lottie do that was so bad, anyway?”

“Remember your training,” said Custer, but it was too late. The twins’ Gifts were awake and responding to the anger they felt. Shadows stretched and deepened until the darker corners of the blue room became impenetrable black holes. The gusting wind picked up speed as it circled under tables, along bookcases, and around the light fixtures, moaning as it went.

“Control yourselves, troubletwisters!”

They did try, but the angry boom of Aleksandr’s voice only worsened the force of their Gifts. And the chaos wasn’t confined only to the blue room, either. Just as the mirror could send their images and voices to the rest of the Grand Gathering, so too could it send their Gifts. One by one the candles in the Hall of Mirrors turned black and shed no light. The giant chandeliers began to sway. Wardens wearing hats clutched them tightly to their heads as the gale picked up strength.

Jack and Jaide tried their best to control their Gifts, but the presence of so many Wardens made them restless and seemingly keen to show off. A miniature hurricane did a wild jig around Aleksandr, while thin tentacles of shadow tried to tie themselves in knots in his hair and beard.

“Jack, Jaide, not here.”

Their father’s voice cut gently but firmly through the crowd. The soft reproach brought blushes of embarrassment to both twins’ cheeks, and sufficiently dampened their anger at Aleksandr so that their Gifts began to creep back through the mirror. The light of the candles returned.

Aleksandr tried to put his hair in order, but it stayed standing up in patches.

“This is inexcusable,” he said. “All troubletwisters are immediately expelled for the remainder of the Gathering.”

“They mean well —” Hector tried to object.

“They are a disruption and an irrelevance. They will leave at once!”

Jack and Jaide looked shamefacedly at their grandmother, who nodded, not unkindly.

“Thank you for trying,” she said, “but there’s nothing more to be done now. Go on.”

“But, Grandma —” Jaide started to say.

“Wait outside. I’ll come to you when it’s over.”

The twins reluctantly made their way through the clutter and the tapestry that led to the top floor of the house via the secret door that linked the main house to the blue room with an impossibly short stair created by their great-grandfather, a Warden with a Gift for architectural magic. Jack’s face felt hot the whole way, while Jaide bit sharply down on her tongue to stop herself from saying something she might regret. As the door closed behind them they heard Aleksandr calling the Grand Gathering to order.

“What happened?” asked Ari, appearing at the top of the stairs with eyes round in surprise. “Is it over already? I thought you’d be at it for hours.”

Jaide freed her tongue. “They might be, but not with us. They kicked us out!”

“Don’t feel bad,” said Kleo, padding up the stairs past Ari to give Jaide a head-bump. “Warden Companions weren’t allowed, either.”

“No … that’s not it … oh!” Jaide flapped her hands at her side, and nearly succeeded in actually flapping herself right up to the ceiling. “That man’s such a pain.”

“Which man?” asked Ari.

“Aleksandr,” said Jack, taking over the explanation, as he sensed his sister was close to another explosion. “He wants to trap Grandma X’s sister in the Evil Dimension forever. And she’s going to let him.”

“That doesn’t sound like her,” said Kleo.

“Maybe she doesn’t really mean to,” said Ari. “Maybe she’s going to do something about it behind his back.”

“What can she do?” said Jack. “She can’t take on The Evil all on her own.”

“That would be very unwise,” agreed Kleo.

“They kept talking about some catastrophe forty-five years ago, when Lottie was lost,” said Jaide. “Do you know what that was?”

Both cats shook their heads.

“You could look it up in the Compendium,” said Ari. The Compendium was the pooled records of every Warden’s dealings with The Evil, and it also provided valuable information on the Wardens themselves, when the information could be understood.

“We could do that, if the Compendium wasn’t in the blue room,” said Jack. “Maybe later, when it’s all over.”

“Is that you, kids? Are you done?”

Their mother’s voice floated up from ground level.

“She cooked dinner for you,” said Kleo.

“How bad is it?” asked Jaide.

“It looks … edible,” allowed Ari.

“On our way!” Jack called back. Susan Shield’s meals were notoriously bad, but his stomach was empty and the very thought of food temporarily put all other concerns from his mind.

Jaide followed her brother down the stairs with feet as heavy as her heart. How could Grandma X even pretend to abandon her sister like that? Whatever Project Thunderclap was, it wasn’t ready to go just yet, or Aleksandr wouldn’t be warning people off. There was still time, so why wasn’t Grandma X insisting they use it?

Halfway down the stairs, the lights flickered. Jack looked up, but didn’t think anything of it. The house was old. An electrician had once come to put extra outlets in the twins’ room, but after an hour inspecting the wiring declared his amazement that anything worked at all.

“What’s the Warden of Last Resort?” Jack asked.

The cats exchanged a look.

“Why do you ask?” Kleo wanted to know.

“It was just something Aleksandr said at the beginning of the Gathering. He said it had been called by the Warden of Last Resort. He wasn’t talking about Grandma, was he?”

The lights flickered again, this time accompanied by a prolonged crackling sound.

Jack looked up at the bulb above his head. Its color had changed from a soft yellow to a harsh blue. Tiny sparks shot from it and discharged harmlessly into the air.

“That’s weird.”

“Jack …?”

It was Jaide who spoke. She had fallen behind without him noticing. He turned and saw her standing five steps above him, balanced precariously in mid-step with a hand touching a banister on either side, as though afraid she might float away.

Every long, red hair on her head was standing on end.

“Jaide! Are you all right?”

“Yes,” she said, nodding quickly. “But I think —”

The crackling sound came again. This time the lights flared green, and bright sparks ran down Jaide’s arms into the stairs.

“Jack, I think something’s coming!”