FLEETFOOT LED ERNST down a long flight of stairs and an equally long corridor with thick wooden doors set at intervals along each wall.

“We are deep in the bedrock now,” the little gray explained. “Where it is easier to find chambers of this size.”

Ernst was about to ask him to elaborate when they reached the end of the hallway. A scarred door no bigger than his escort stood before them. The mouse pulled a ring of keys from his belt, chose one, and unlocked it.

The rat had to duck to enter the room. On the other side, even straightened to his full height, he was dwarfed by the massive space. At least ten rats tall, the ceiling was shrouded in darkness. A walkway several feet overhead was lined with torches, illuminating a nightmare.

In the center of the chamber, stock-still and staring, was a life-size cat. Two times Ernst’s full height, its metal body was intricately detailed down to the tufts of fur on its ears, and its glittering, bejeweled eyes. Ernst Listz had seen many things in his life, but none had brought bile to his throat the way this did.

“Good heavens,” Ernst whispered, nearly choking. “Is it alive?”

The mouse shook his head and trembled despite the stillness of the beast. “It’s a clockwork,” he explained, leading the way into the chamber. “A toy. Silent, scentless, with no need to breathe. Impossible to hear coming. We call them the Breathless.”

“Them? There’s more than one? What monster considers this a toy?” Ernst wondered.

Fleetfoot whispered with a reverence born of fear, “Drosselmeyer.”

The closer Ernst got, the more the cat-fear subsided, changing into fascination of the metal and cloth that replaced flesh and fur. “It’s a made thing?”

“Devilish,” the mouse acknowledged. “When the clockmaker first came to Boldavia, he made these for the King Above. The man is allergic to cats. One of the reasons we have done so well on the island. Few predators.”

Ernst could only imagine life without the feline threat. How lucky to walk the streets of a city unafraid. He could leave his sword behind and feel safe as a mouse in a hole.

“How does it work?” he asked.

“Like a cat. Only faster. It swallows mice whole.” Fleetfoot mounted a ladder that leaned against the side of the beast. “The belly here is a cage. Mice were held here. Some died in the crush. When the Breathless was full, it would go down to the ocean and sit beneath the waves. Machines have no need of air.” The mouse mopped his forehead with a paw.

Ernst shuddered. A terrible name to describe both the killer and its victims. “They all drowned, trapped inside that thing?”

Fleetfoot nodded. “And then . . .” He reached out a finger and unfastened something on the underside of the construct’s stomach.

A soft whir sounded from somewhere inside the cat, like a dreadful purr. From where he stood, Ernst could see a seam split apart the soft velvet underbelly and drop, swinging from two hinges. The floor of the cage was a trapdoor.

“It would dump the bodies, wash away any trace, and return to the castle to do it all over again.” Fleetfoot fixed the rat with wide eyes. “The Breathless do not sleep, and they are always hungry.”

Ernst shook his head in slow horror. “I have never heard of such a thing,” he admitted. “This is a tale to be told across Rodentia.”

“They’re an atrocity that must never happen again,” Fleetfoot squeaked. “The Queen’s sons will save us. It has been foretold.”

By the Queen herself, no doubt, Ernst thought. It was worse than he had imagined. Not a backward country Queen, but an insane one, with a monster in her house, and a litter of messiahs waiting to be born. Suddenly, starving quietly in Vienna seemed the simpler choice.

Fleetfoot climbed back down the ladder. “It cost many lives to subdue this beast. We have learned much from studying its workings. Just one of ten in all. Of the others, some were destroyed, and a few fell into disrepair after the clockmaker left Boldavia.”

“Left?” Ernst gasped. “Why?”

The little mouse allowed himself a proud smile. “Our Queen. She poisoned the human princess and sent the clockmaker on a fool’s errand for the cure. One small nut in all the kingdoms of flora and fauna. She has given us seven years of peace. And now she will give us seven princes to bring about a golden age.”

Ernst gave Fleetfoot a respectful bow. “I had no idea, sir. The Piper was generations ago, but this, this is war.”

Fleetfoot returned the bow. “And now you begin to understand, Herr Listz. Our kingdom has need of one who can teach her children about the world of Men. Languages, fencing. How they think, how they die. They will need to know all of this to scour the kingdom of mankind. You have lived with one paw in their realm for a long time, sir. You are a valuable asset.”

Ernst gave the clockwork cat one last look; the emerald eyes danced in the firelight, far from real, but all the worse for it. “I’ll do what I can,” he promised.

He would teach the boys swordplay, strategy, diplomacy, and language, all useful things in warfare. But, looking at the clockmaker’s creation, he wasn’t sure if it would be enough.