“They’re League fighters,” said Hester flatly. “I recognize those flared engine-pod cowlings. Murasaki Fox Spirits.”

She sounded scared, and with good reason. She and Tom had been careful to avoid the Anti-Traction League these past two years, for the Jenny Haniver had once belonged to a League agent, poor dead Anna Fang, and while they had not exactly stolen her, they knew the League might not see it that way. They had expected to be safe in the north, where League forces were spread thinly since the fall of the Spitzbergen Static the year before.

“Better go about,” said Hester. “Get the wind on our tail and try to outrun them, or lose them in the mountains.”

Tom hesitated. The Jenny was much faster than her wooden gondola and scrapyard engine pods made her look, but he doubted she could outrun Fox Spirits. “Running would just make us look guilty,” he said. “We’ve done nothing wrong. I’ll talk to them, see what they want…”

He reached for the radio set, but Pennyroyal grabbed his hand. “Tom, no! I’ve heard about these white ships. They aren’t regular Anti-Traction League at all! They belong to the Green Storm, a fanatical new splinter-group who operate out of secret airbases here in the north. Extremists, sworn to destroy all cities — and all city people! Great gods, if you let them catch us we’ll all be murdered in our gondola!”

The explorer’s face had turned the colour of expensive cheese, and pinheads of sweat gleamed on his forehead and his nose. The hand that gripped Tom’s wrist was shaking. Tom couldn’t imagine at first what was wrong. Surely a man who’d survived as many adventures as Professor Pennyroyal could not be scared?