"We should leave something, a headstone or some message," said Gregor. But writing in stone was no small matter. He had intended to write a few sentences about what happened, but it was an effort even to scratch one straight line into the side of the cliff with his sword. As he stood considering the wall, waiting for inspiration, Luxa came up and added the thin, beaklike appendage that turned the line into the scythe. Into a mark of secret.

  "It will be a warning to any that follow us," she said. "And it will be a fitting marker for the nibblers' graves."

  And then Luxa did something that made Gregor feel both remarkably close to and a million miles away from her. Flinging away the cloth from her nose, she kneeled on the ground and placed her crown in front of her. Crossing her wrists, she held her hands, palms down, over the gold circle, and said in a loud voice:

  "Upon this crown my pledge I give.

  TO MY LAST BREATH, I HOLD THIS CHOICE.

  i will your unjust deaths avenge, All here who died without a voice."

  The words reverberated around the tunnel. It was not an impromptu rhyme, something she had made up off the top of her head. There was a specific ritual and a grim, formal tone to the lines. Gregor was certain it was an oath. Something you swore to fulfill or died trying to. It came from such an agonized place within Luxa that Gregor wanted to wrap his arms around her. But the oath had pushed him away from her, too. Had reminded him that he was just a visitor in a strange land where people vowed vengeance and crowns mattered and queens were off-limits to him.

  Watching her rise, Gregor could no longer see Luxa the twelve-year-old girl who'd been searching for clues about her mouse friends. What he saw was the future head of Regalia, and its considerable armies, and that the rats were somehow going to pay with their blood.

  Something was happening in the tunnel. Faint whispering sounds, buzzes, a rustle of wings. Gregor remembered what Howard had said, about how a lot of creatures lived in Hades Hall. They had been keeping a low profile so far, but they were around, watching, listening, and now reacting to Luxa's little speech. She heard the reaction and for some reason that Gregor didn't understand, she smiled.

  The moan startled them. Zap brightened her beam and they saw a slight movement in the field of stillness. The tip of a tail shuddered. Disregarding Howard's warning about touching the creatures, Luxa raced to the mouse's side and crouched beside him, stroking his fur. He could not speak.

  "Let's get him to Howard," said Gregor. Together, he and Luxa loaded the mouse onto Ares's back. Gregor tossed his leg over his bat's neck, but Luxa remained on the ground. "Aren't you coming?" he asked.

  "No, Gregor. We will stay and make sure no others still have light," said Luxa. In the Underland, the word "light" could be interchangeable with the word "life."

  Gregor looked at the victims. "We'll come back and help," he said.

  "You do not have to," said Luxa. "Aurora and I can manage."

  "We will come back," Ares said.

  Gregor and Ares delivered the barely conscious mouse to Howard and returned to the base of the cliff. One by one, they checked each body. Some were obviously dead. Some it was impossible to tell, so they felt for a pulse or listened for a whiff of breath coming from their nostrils. There were no other survivors.

  Back at the campsite, Gregor scrubbed himself at a nearby stream, but he could not seem to get the smell of the dead mice from his pores. And the images of those bodies ... well, he knew those would revisit him for a long time in his dreams.

  Howard worked long and hard over the injured mouse. One of his front legs was broken, so Howard set the fracture. He put a salve on the mouse's raw and bloody paws. After about an hour of periodically getting him to take spoonfuls of water, Howard made a thin gruel of fish, bread crumbs, and broth and got the mouse to eat a little. The water and food revived him enough for him to speak a few words, starting with his name, Cartesian. Howard was able to ascertain the extent of Cartesian's injuries better now. The mouse had badly bruised ribs, although they did not seem broken. He'd received a blow to the head. Dehydration and hunger had also taken their toll. It was not enough information to find out exactly what had happened to Cartesian, but it was enough to treat him. Howard made a poultice for Cartesian's head, gave him some painkiller and a second medicine to reduce swelling, and continued to feed him.

  Boots wanted very badly to help, so Howard gave her the job of singing the mouse to sleep. She squatted down a few feet away and softly sang little tunes she knew from home. These were mostly theme songs from preschool shows she watched on TV. Then she launched into her Underland repertoire, which included the songs about the spinners, and the fish, and the bats.

  "Bat, bat,

  Come under my hat, i will give you a slice of bacon

  And when I bake, I will give you a cake,

  If I am not mistaken. "

  Then she sang the stanza from the one about the queen and the nibblers and pouring tea, because she thought, as a mouse, Cartesian would like it best.

  "Catch the nibblers in a trap. Watch the nibblers spin and snap.

  Quiet while they take a nap.

  Father, mother, sister, brother,

  Off they go. I do not know

  If we will see another. "

  Cartesian slowly drifted off to sleep, and Howard praised Boots for her excellent singing job. Enamored with her newfound talent, Boots went around to everybody trying to sing them to sleep. Half the party were so tired they genuinely fell asleep; the other half pretended until Boots dozed off herself. Then Gregor, Luxa, Howard, Aurora, Nike, and Ares gathered for a consultation in the glow of Photos Glow-Glow's bulb.

  "Well, as tragic as our findings today have been, at least we know we have kept to the nibblers' trail," said Howard.

  "It is not much to our credit," said Luxa. "We chose this path because it was the only way out. We can be sure that we follow them to the far side of Hades Hall."

  "And then?" asked Gregor.

  "And then what?" asked Luxa.

  "And then you're going to keep following them, aren't you? Instead of going back to Regalia," said Gregor. She didn't answer, but he knew he was right. She wasn't going home. Not after she'd kneeled on the ground and said that stuff over the crown.

  "We cannot do that. We have injured who must be returned home," said Howard. "And I believe there is enough evidence to make a case before the council, now that we have Cartesian for a witness."

  "The rest of you will go back. Aurora and I will continue after the nibblers," said Luxa. "Someone must stay on their trail."

  "But it will not be you, Cousin. I will drag you back to Regalia before I would leave you here alone," said Howard.

  "She made some kind of oath," said Gregor. "Back at the cliff."

  "Oath?" Howard looked at Luxa and his face fell. "Not 'The Vow to the Dead'?" he said in a hushed voice. Luxa nodded. "Oh, Luxa, what have you done? You are not even of age. You do not reign. The army does not move at your command. How mean you to fulfill it?"

  "The only way I can," said Luxa. "I will go after the nibblers, and the council will send the army after me."

  "They didn't send an army when you got caught in that rat maze," said Gregor.

  "Because they thought she was dead," said Howard. "They will now. They must. Especially if she has said the vow."

  "How will they even know?" said Gregor. "It's not like the humans have scouts in Hades Hall."

  "Do you think only human ears matter?" scoffed Photos Glow-Glow. "The fliers heard her; that nibbler heard her; Zap heard her and has already told me. You are in Hades Hall, not the Dead Land. Who knows how many other creatures sat in the dark listening?"

  "A lot," thought Gregor, remembering the strange noises that had followed Luxa's vow. That's why she had smiled. She had wanted them to hear.

  "Half the Underland will know she said it in a matter of hours; she cannot take it back," said Howard.

  "Nor would I if I could," said Luxa.

  "But
you're only, like, twelve," said Gregor. "Does it even count?"

  "In this case, it counts," said Howard. "By the time word of the vow reaches the council it will already have reached our enemies. There will be no way to call it back or deny it. And given the circumstances, we will have only one option."

  "What's that?" said Gregor.

  Luxa gazed at him evenly. "I have just declared war on the rats."

  ***

  CHAPTER 15

  "So this is how a war starts," thought Gregor.

  Not with two armies facing off, waiting for the signal to charge. Not with a wave of rats invading the avenues of Regalia. Not with a formation of bats swooping down on an unsuspecting colony of rats. It begins much more quietly. In a room, on a field, in a remote tunnel when someone who has power decides the time has come.

  "No," he said. "We have to find some way to stop it."

  "It is too late," said Luxa. "It is ironic. I could never start a war in Regalia. I can barely get leave to go on a picnic. But here, away from my city, I am free to make momentous decisions."

  "Then maybe they should keep you locked up in your city, if you're going to go around declaring war!" said Gregor.

  "Did you not see the bodies?" exclaimed Luxa. "What would you have me do, Gregor? Sit by while my friends are driven to their death?"

  "We do not know exactly what plans the gnawers have for the nibblers, Cousin," said Howard. "But we do know they have a history of moving them from place to place. Perhaps the majority of the nibblers have already reached their new home in safety."

  "That they were forced from their old home is not acceptable!" said Luxa. "That hundreds lie dead from the journey is not acceptable!"

  "Okay! But maybe you might want to consider some other options besides waging war!" said Gregor.

  "As in?" said Luxa.

  "I don't have any off the top of my head," said Gregor. "But I bet I can come up with something a little less extreme."

  "Well, when you do, I would love to hear it," said Luxa. "I am sure it will dazzle us all." She was mocking him. He might as well have been talking to Ripred. Gregor stared at her a moment. "It was pretty easy, starting a war," he said.

  "It was not difficult," said Luxa.

  "I wonder what it will take to get out of it?" said Gregor.

  "I doubt you will ever find out. Since you are going home," said Luxa. "We, on the other hand, must stay and live here."

  They did not take a watch together that night. Gregor didn't want to argue with Luxa. What he wanted was to think up an answer to her question that would dazzle everyone. The problem was... he didn't know what else could be done about the rats abusing the nibblers. If they didn't use force, how could the humans stop them? He knew the rats would not listen to talk. Since the plague, the humans had given the rats a lot of food and medicine to make up for unleashing the disease, but it had not erased the bitterness.

  It was even more complicated because the rats did not have a leader to negotiate with. After King Gorger had died, the rats had splintered into groups. The plague had thrown them into even greater chaos. Now there was the Bane. He might be the next king. But then, what about rats that didn't follow him? Like Ripred and his gang. What about rats like Lapblood, who had been with Gregor on the quest to find the cure to the plague? She'd been trying to keep her pups alive. That's the main thing he knew about her. Would she support the Bane? If he was alive? If Ripred hadn't killed him?

  Who exactly was Luxa declaring war on? The rats who had driven the nibblers off the cliff? Anyone who supported the Bane? Or just every rat, regardless of what they thought or stood for? Whatever Luxa had in mind, Gregor guessed that if a war really did begin, no one was going to take the time to interview a rat on its political position before they killed it.

  Gregor found himself wishing very badly that he could talk to Hazard's father, Hamnet. Of course, Hamnet was gone. Killed months ago by the ants in a battle back in the jungle. Ten years earlier Hamnet had been one of Regalia's top soldiers. During a battle, he had inadvertently caused a dam to break, which resulted in the drowning deaths of not only an army of rats but also humans, bats, and the innocent rat pups sheltering in nearby caves. Hamnet had gone temporarily mad and then disappeared. Many years later, he had resurfaced in the jungle with his little son, Hazard, to act as Gregor's guide. Gregor remembered Vikus, who was Hamnet's father, begging him to return to Regalia. "What do you do here that you could not do there?" To which Hamnet had replied, "I do no harm. I do no more harm." Hamnet knew if he returned to Regalia, they would make him fight again.

  Hamnet had tried to explain his position on war to Luxa. How it did no good. How innocent creatures died and, in the end, how it only increased the already intense hatred between the rats and the humans. Hamnet believed that the least amount of violence used, the better.

  The things he'd talked about had made real sense to Gregor. Then an army of ants had appeared to destroy their precious plague cure and they had all ended up fighting, anyway. And that's when Hamnet had died. But what he had said ... everything he had said ... had been right. Deep inside, Gregor was sure of this. Only he did not know how to work his ideas into some kind of argument with Luxa. Not here. Not with the dead mice and the Bane running loose and everything. And why would she listen to him, anyway? Why would she listen to him say violence was a bad choice when he had hacked up a couple hundred snakes with a smile on his face? He drifted off to sleep feeling heartsick and confused. And without one dazzling idea.

  When he awoke the next morning, the bats had already been fishing. Photos Glow-Glow and Zap were making loud smacking noises as they wolfed down their breakfast. Along with the fish, Howard had given them some other picnic treats that had spoiled ... mushrooms in cream sauce, rotted greens.

  The bats and Temp were only eating from the river now, but the remaining picnic food was running low. There were a few loaves of stale bread, some cheese, some dried vegetables, and a couple of cakes. Gregor looked over the supplies and thought about Boots wailing for food and water in the jungle. It had been unbearable. He sighed and picked up a raw fish, hacking off a piece with his sword. Better to save the picnic food for the kids.

  Howard must have made a similar decision, because he was cracking open shellfish with a rock. "Try this," he said to Gregor, handing him a slimy thing on a half shell. "It is considered a delicacy at the Fount."

  Gregor dumped the contents of the shell into his mouth. His teeth chased the slippery glob around his mouth for a few chews then he swallowed. Ugh. "I can see why," he said, trying to be polite.

  "There are plenty," said Howard, shoving a stack toward Gregor.

  "He does not want them, Howard; they are disgusting," said Luxa. She was expertly flaying the skin off a fish.

  Gregor agreed with Luxa, but because he was angry with her and liked Howard he ate a few more of the shellfish just to prove her wrong. He drank some water to wash the taste out of his mouth, but then he could feel the things sloshing around in his stomach.

  Cartesian awoke and seemed to have gained a little of his strength back. He was woozy from the medicine. "Where are the others?" he kept asking.

  "We are going to get them now," said Luxa gently.

  But he kept repeating, "Where? Where are the others?"

  Howard got Cartesian to eat some ground-up fish and gave him another dose of painkiller. Soon the mouse was sleeping again. "I'm afraid I shall have to sedate him on the entire journey back to Regalia," said Howard.

  Space on the bats was becoming an issue. Hazard was still supposed to be lying down, so he and Luxa filled up Aurora's back. Gregor had Boots and Temp with him on Ares. And Howard settled Cartesian on Nike's back. "We are becoming a flying hospital ward," said Howard, "what with Hazard and Cartesian. We are lucky no one else is hurt."

  Boots indignantly held up her finger. The nick was all but invisible now. "Me!" she said, shocked that she'd been overlooked.

  "Oh, my goodness. Did I forget you,
Boots? We had better put some medicine on that," said Howard.

  It did not take more than an hour to cover the stretch of Hades Hall that was flat. Then the tunnel began to tilt upward as rapidly as it had dipped. If the trip down had required patient navigation from the bats, they had been allowed to coast for much of it. Now that they were flying upward, it required real physical exertion, but they seemed to be moving faster. Thalia began to fall behind as the morning wore on. By lunch it was clear the little bat was done in.

  "I know it is tight, but we are going to have to double up," said Howard, handing Gregor a nice, freshly cracked shellfish.

  Gregor tossed it back without chewing. That was better somehow. "How do you want to do it?"

  "We must put Thalia on Ares. Temp, could you ride on top of Thalia?" asked Howard.

  Gregor remembered the first time Temp had flown. How much he had hated it. "Do it, I can, do it," said the cockroach, but Gregor knew it would be a challenge for the bug to be the top of a flying-bat pyramid.

  "Cartesian is heavy, and I as well, so I do not think Nike can manage more than Boots," said Howard.

  Gregor knew where that left him. With Luxa.

  "If that is all right," said Howard.

  "Fine," said Gregor.

  Luxa was probably no more thrilled about the travel arrangements than Gregor, but there was nothing either of them could say. When it was time to move on, Gregor took a seat on Aurora's neck, facing forward. Luxa sat with her back to Gregor's, so she could amuse Hazard as they flew. The boy lay facing Luxa, with his feet on her lap.

  For the first few hours, Luxa basically ignored Gregor. She passed the time by playing word games with Hazard. When that grew old, she told him the Underland equivalent of the famous fairy tale "Little Red Riding Hood." In Luxa's version, Little Red Riding Hood was a girl who left Regalia on her bat to visit her grandmother at the Fount. Against instructions, she strayed from the path. Instead of going into a forest, she was lured into tunnels by some lovely mushrooms. There she ran into the Big, Bad Rat. The rat didn't kill her because she was flying too high. Instead, he was so friendly that Little Red Riding Hood told him all about her plans. When Little Red Riding Hood arrived at her grandmother's house, the Big, Bad Rat was waiting for her, disguised as her grandmother. They did the whole "But, Grandmother, what big eyes you have!" routine. Then the grandmother appeared and killed the Big, Bad Rat and she and Little Red Riding Hood threw the rat's body in the river. The moral of the story -- never trust a rat.