At the end of Dog Star Court, a stairway led down through the deck plates into the engine district. As Wren went clanging down the stairs, a summery smell came up at her, and she heard flakes of rust dislodged by her boots falling amid the heaped hay below. Once this part of the city would have been full of life and noise, as Anchorage’s engines sent it skating over the ice at the top of the world in search of trade. But the city’s travels had ended before Wren was born, and the engine district had been turned into a storeroom for hay and root vegetables, and winter quarters for the cattle. Faint shafts of moonlight, slanting through skylights and holes in the deck plates overhead, showed her the bales stacked up between the empty fuel tanks.

When Wren was younger, these abandoned levels had been her playground, and she still liked to walk here when she was feeling sad or bored, imagining what fun it must have been to live aboard a city that moved. The grown-ups were always talking about the bad old days, and how frightening it had been to live in constant danger of being swallowed up by some larger, faster city, but Wren would have loved to see the towering Traction Cities, or to fly from one to another aboard an airship, as Mum and Dad had done before she was born. Dad kept a photograph on his desk that showed them standing on a docking pan aboard a city called San Juan de Los Motores, in front of their pretty little red airship the Jenny Haniver, but they never talked about the adventures they must have had. All she knew was that they had ended up landing on Anchorage, where the villainous Professor Pennyroyal had stolen the ship from them, and after that they had settled down, content to play their roles in the cozy, dozy life of Vineland.

Just my luck, thought Wren, breathing in the warm, flowery scent of the baled hay. She would have liked to be an air trader’s daughter. It sounded a glamorous sort of life, and much more interesting than the one she had, stuck on this lonely island among people whose idea of excitement was a rowboat race or a good apple harvest.