Gogmagog tells the story of an epic journey through the sixty-mile long ghost of a dragon. We travel by boat, a rickety steam launch captained by Cady Meade, a veteran taxi pilot on the river Nysis. In her heyday she carried people and goods from the thriving seaports of the estuary into Ludwich, the capital city. But that was years ago. Now she's drunk, holed up in a rundown seaside resort, telling her bawdy tales for shots of rum. All that's about to change, when two strangers seek her out, asking for transport, one of whom - a young girl - is very ill, and in great danger. The other, an artificial being of singular character, has secrets hidden inside his crystal skull. And so begins the voyage of the Juniper.

The Nysis is unlike any other river. Mysteries unfold with each port of call. Not many can navigate these channels, not many know of its whirlpools and sandbanks, and of the ravenous creatures that lurk beneath the surface. Cady used to have the necessary knowledge, and the powers of spectral navigation. But her glory days are well behind her now.

This might well be her final journey.