“Of course,” I said. “Shall we be off?”

A wan smile crossed her face. Retrieving a pocketknife from her person, she cut through the cable connecting to Crankshaft. A moment later, I had worked out how to disengage us from the cradle below, and we began drifting upwards.

“Crankshaft will be fine,” I said, more to reassure myself than anything else. “He had enough oxygen to last for some time, and we are not far from the city. Minnow can guide him back.”

My mistress did not answer. She had spread out a chart, and was determining our course from here.

It took a little time to adjust myself to the controls, but before long we had left the crevasse.

I directed us to the east...