The lights went out, too, and in the bitter-cold darkness more tears flooded Kate’s eyes, not for herself but for the thought of the Silver Arrow spending the rest of its days here at the bottom of a cold, dark lake in the middle of nowhere, with only cold, silent fish to keep it company. That was one of the first things Uncle Herbert said: Never let the fire go out. It was what the Silver Arrow had been most afraid of. And now the firebox was as dead and dark as when she’d first seen it. She wondered what it felt like, cold water flooding into your brain and putting out your thoughts. Did it fall asleep and dream? Or was it just—nothing?

Shivering uncontrollably, Kate forced her numb fingers to grip the door handle and braced herself for what she was about to do.

But before she could open the door, the train dropped and settled even farther. It was sinking into the mud! Only now did Kate’s mind go completely blank with panic. If there was anything worse than being frozen and drowned, it was being smothered in freezing mud, too. Buried alive. She scrabbled furiously at the window, but she couldn’t feel her fingers anymore—

Then a very weird thing happened: They fell.

She felt the train break through the mud and drop through air, and for a second Kate was weightless, and her stomach flipped. Then, with a crash like a thousand pianos being dropped from a million-story building, the Silver Arrow landed on something solid.

Nobody moved. Gradually Kate became aware that water wasn’t coming in anymore. In fact it was draining out.

“W-what is this?” Tom said. “What h-h-happened?”

“N-no idea.”

Cautiously, very cautiously, she wondered if it was possible that they weren’t going to die. She slowly opened the window and looked outside.

They weren’t underwater or buried in mud. They were in an enormous underground room. It was completely round and lit by orange light from a giant roaring fireplace. The air was warm.

“Heat!” Tom pushed past Kate and out of the cab.

A silver fish from the lake was still flopping around on the floor of the cab. The porcupine looked at it thoughtfully, and then he ate it.

Animals, Kate thought.

Outside a man was standing with his back to the fire, watching them. His face was in shadow, but Kate had a pretty good idea who he was.

“Come on,” Uncle Herbert said. “Come get warm. You must be freezing.”

Tom was already by the fire, and Uncle Herbert bundled a blanket around his shoulders. Kate climbed down and took a blanket, too. Then she climbed back up, wrapped the blanket around the shivering porcupine, and carried him down to get warm. Only then did Kate accept a blanket for herself and take her place by the fire.

She could feel that they were deep underground.