The dragon keepers and the fledgling dragons are forging a passage up the treacherous Rain Wild River. They are in search of the mythical Elderling city of Kelsingra, and are accompanied by the liveship Tarman, its captain, Leftrin, and a group of hunters who must search the forests for game with which to keep the dragons fed.

With them are Alise, who has escaped her cold marriage to the cruel libertine Hest Finbok in order to continue her study of dragons, and Hest's amanuensis, the Bingtown dandy Sedric.

Rivalries and romances are already threatening to disrupt the band of explorers, but external forces may prove to be even more dangerous. Chalcedean merchants are keen to lay hands on dragon blood and organs to turn them to medicines and profit. Their traitor has infiltrated the expedition and will stop at nothing to obtain the coveted body parts.

And then there are the Rain Wilds themselves: mysterious, unstable, and ever perilous, its mighty river running with acid, its jungle impenetrable, and its waterways uncharted. Will the expedition reach their destination unscathed? Does the city of Kelsingra even exist?

Only one thing is certain: the journey will leave none of the dragons nor their human companions unchanged by the experience.