regor didn't even wait to change, he just took off at a run. Underlanders did not use the word "emergency" lightly. What had happened? Had Boots fallen and hurt herself? Choked on something? If so, why hadn't she been brought directly to the hospital? Or was it some other kind of emergency? It was clear that she had worn out the patience of all of the other code-breakers. Had one of them done something? Maybe Ripred had returned and threatened her in some way and she had lost it. It was unlikely the cockroach or bat had harmed her. And the mouse had been so weak it could hardly move. But that green spider! Maybe it had trapped her in its web. Gregor still had a hard time trusting spiders. His visit to their land, when he had thought they were going to have him for dinner, had been anything but reassuring.

As he sprinted down the narrow hallway his foot slid in something. Blood. Someone had bled, leaving a trail all the way to the door. "Boots!" he cried. If they had hurt her, if they had harmed one hair on her head —

Boots flew into the hall. "Gre-go! Gre-go!" she called in distress.

He picked her up, running his hand through her curls, looking for injuries. "What's the matter? Are you okay? Did somebody hurt you?"

"No, I am okay. In here! In here!" Boots tugged on his shirt to make him enter the room. Totally confused now, Gregor stepped inside. There, crouched in the center of the stone floor, was his other sister, Lizzie.

"Oh, no," said Gregor. He had no idea how she'd gotten here or why she'd come. But he knew this was no time to ask. While she did not seem to be bleeding, either, she was hurting, because Lizzie was in the middle of one of her panic attacks. She was panting for air, shaking like a leaf, and he could see the sheen of sweat on her palms. His dad had explained this to Gregor. Everybody had a fight-or-flight response hardwired into them. When you were in danger, it triggered, pumping adrenaline through your body. This helped you either to fight off an adversary or run like crazy. Gregor guessed he must have been having a panic attack of sorts in the museum when he finally admitted what "The Prophecy of Time" had in store for him. That was pretty major. But in people like Lizzie, it didn't take much to set off the response. Sometimes she would have an attack for no apparent reason at all. She would be in a state of extreme terror, but there would be no one to fight and nothing to run from.

There was something real today. Even the thought of coming to the Underland had always been enough to give Lizzie an attack. Now she was actually here, facing off with a room full of giant scary creatures. They were doing nothing to threaten her. The mouse, bat, and spider were huddled in their rooms. The cockroach had disappeared into its alcove entirely and drawn the curtain shut. Temp had stayed, because he would never abandon Boots, but he had positioned himself under the table. Only Nerissa was near Lizzie, trying to soothe her and looking on the verge of some kind of attack herself. Gregor swung Boots down and crossed to Lizzie. "Whose blood is that?" he asked Nerissa.

"Hermes. He flew her from the Overland. They were ambushed by gnawers and he was clawed. She is not injured, but we cannot quiet her," said Nerissa.

"Yeah, I know. She gets like this sometimes," said Gregor. He sat behind Lizzie, pulled her back into his arms, and held her. "Hey, Liz. It's okay. It's okay. Nobody here is going to hurt you."

"Oh! Gregor! You have to — come home! Now!" Lizzie got the words out.

"Why? What happened?" asked Gregor, suddenly feeling scared, too. What had happened that was so dire that Lizzie had forced herself to come to the Underland?

"Grandma — in the hospital. Dad — very sick again. I can't take — care of him!" said Lizzie.

"What? But Dad's letters keep saying everything's okay." Had this stuff just happened or had his dad been concealing things to keep Gregor from worry? "What about Mrs. Cormaci?" asked Gregor. She had always been there for them before.

"Stays with — Grandma. Really tired. You have to — come home!" said Lizzie. And with that, she threw up all over the floor.

Gregor held her while she heaved, trying to make sense of what she had said. His problems had been so overwhelming down here, he had given little thought to what was going on back home. Grandma in the hospital? His dad sick again? It must really be bad.

When Lizzie finally stopped retching, he picked her up and carried her over to the side of the room. He just sat there with her on his lap, feeling her shake. "It's okay. It's going to be okay, Liz. I'll take care of it," he said. He had no idea even where to begin.

"I brought — a bag. In my—backpack," Lizzie said.

Her backpack was sitting next to the pool of vomit. "Hey, Boots! Can you bring me Lizzie's backpack?" Gregor asked.

"I can do it," said Boots, running over to fetch him the backpack. "I can get the bag, too!" Her chubby little fingers struggled with the zipper, but she got the pack open and pulled out a folded paper lunch bag.

Gregor opened the bag up and put it to Lizzie's face. "Breathe. Nice and slow now. Nice and slow."

This helped, because people having panic attacks got too much oxygen into their systems, and breathing into a bag gave them more carbon dioxide. Gregor rubbed the tense muscles in Lizzie's back, and the combination of that and the bag seemed to calm her down a little.

"It's okay, Lizzie. You're okay," said Boots, patting her big sister's hand. Lizzie's attacks were one of the few things that upset Boots. "I am here."

Nerissa summoned a pair of Underlanders, who quickly came in, cleaned up the vomit, and left. Then all of the creatures sat still, as if they knew any movement on their part would only increase Lizzie's anxiety, while they waited to see what would happen.

And this was how Ripred found them as he swept into the room. "What's going on in here?" His nose was twitching, clearly registering the lingering throw-up smell. Then his eyes landed on Lizzie, and he became still, too, except for the tip of his tail, which twitched from side to side. An expression came over his face that Gregor had never seen before. If he had to put a name to it, Gregor would have called it tenderness. The rat's voice became positively gentle. "I didn't know we had company. But I bet I can guess who you are. You're Lizzie, aren't you?" Lizzie lifted her face from the bag to take in the giant, scarred rat. "You're Ripred," she whispered.

"That's right. I'm glad to finally get to meet you. I wanted to thank you for all of the lovely snacks you've sent me. They're always the high point of my day," said Ripred.

Gregor could not make sense of Ripred's behavior. Why was he being so nice to Lizzie? He had never been nice to Boots.

Ripred moved in slowly. "Sometimes it helps if you talk," he said. "Do something to distract yourself."

Gregor looked at the rat in surprise. What did he know about panic attacks? Surely he had never had one himself. "My dad does math problems with her," said Gregor.

"Math is good," said Ripred. "What's eight plus seven, Lizzie?"

"Fifteen," said Lizzie.

"You're going to have to do better than that. She's like a math whiz, right, Liz?" said Gregor. It was true. The teachers at school never knew what to do with her. She could solve problems way beyond the rest of the eight-year-olds.

"Really?" asked Ripred. "What's twelve times eleven?"

"One hundred and thirty-two," said Lizzie.

"Harder," said Gregor. "She likes to cube things."

"What's six cubed?" asked Ripred.

"Two hundred and sixteen," said Lizzie.

"How about thirteen?" asked Ripred.

"Two thousand, one hundred and ninety-seven,"

said Lizzie without missing a beat. She did seem to be calming down a bit.

"Try thirty-seven," said a hoarse voice from behind Ripred. It was Heronian. The mouse had managed to raise herself up onto her forelegs.

Lizzie panted a moment and then blurted out, "Fifty thousand, six hundred and fifty-three."

Ripred looked at Heronian for confirmation, and the mouse gave a small nod back. Even Gregor was pretty impressed with that one.

"That's right. Apparently that's right," said Ripred. He started to pace, which was always a sign that he was working something out. "Lizzie? Do you like puzzles?" She nodded. "They can be soothing, too. Oh, I know a fun one. We can do it right here. Would you like that?"

"Okay," said Lizzie. Gregor could feel her shaking start to subside. There was nothing like a puzzle to get Lizzie's attention. He thought of the puzzle book that he had bought her on the street that time. She had volunteered to stay with their sick dad while he'd taken Boots sledding in Central Park, and he had wanted to get her a present. That big, thick puzzle book. She had loved it.

Ripred settled down in a comfortable position a few feet in front of Lizzie. "All right. Let's see. Boots, you go stand by Temp."

"Oh, a game!" said Boots, and scurried excitedly over to Temp.

"Now, Lizzie, from where you're sitting, you can see seven creatures. Two humans, one of whom is an Overlander and one of whom is an Underlander, one bat, one mouse, one cockroach, one spider, and one rat. We've just had lunch and we've each eaten our favorite food. No two of us have the same favorite food. The things eaten were fish, cheese, cake, cookies, bread, mushrooms, and shrimp in cream sauce. Now ready for the clues?" asked Ripred.

"I'm ready," said Lizzie, and clasped her hands before her. She no longer even needed the bag. Ripred spoke quickly and distinctly. "The bat's favorite food is either mushrooms or cake. Cookies are not the cockroach's favorite food. The mouse will eat cheese, but she didn't today. The Underlander's favorite food is either cookies or shrimp in cream sauce. The mushrooms and cookies were not eaten by mammals. The Overlander's favorite food is either cake or bread. So the question is, who ate the cheese?"

"Well, that's totally unfair," thought Gregor. No one could figure that bunch of gibberish out. But it really had settled Lizzie down.

She was staring at the floor, squeezing her hands so tightly her knuckles were white. About thirty seconds passed, then she met Ripred's eyes and gave a small triumphant grin. "You did, "she said.

"Wrong," thought Gregor. Ripred's favorite food was shrimp and cream sauce.

"Hmm," said Ripred, and his tail flicked so hard it made a snapping sound. But his voice was casual. "Temp, suppose you take Boots down to the nursery and let her feed the baby mouses. Would you like that, Boots?"

"Ye-es!" said Boots. Temp pattered out from under the table and she hopped upon his back. Ripred followed them out the door calling, "And no need to come back until I send for you!"

Gregor could hear the other creatures murmuring around the room. They seemed more relaxed and even a little excited. Min, the cockroach, poked her head out of her arch, and Daedalus kept fluttering his wings. Could it be they were just relieved to have Boots out of their hair? No, it seemed like something more had happened. But what exactly?

Just then Ripred strode back into the room. The rat was actually smiling at Lizzie. "So," he said. "So, so, so." He sat up on his haunches and then tipped his head forward in an elaborate bow. "Welcome to the Underland, Princess."