Xandri Corelel has spent six months living among the Ongkoarrat after her unceremonious firing from the crew of the Carpathia, and though she misses her home, she has settled into her new life. Then Diver arrives with news that changes everything.

The Hands and Voices--squid- and whale-like symbiotic aliens--are masters of bio-engineering and grow a wide variety of species of coral. Now they are in the process of creating coral that can withstand vacuum, with a most stunning end goal: To grow entire spaceships out of living organisms. The Starsystems Alliance is desperate to lure the Hands and Voices into the Alliance and bring this new technology into the fold. And the Voices and Hands are willing, with one stipulation.

They will only negotiate with Xandri and the crew of the Carpathia.

Returned from exile, Xandri is given the lead on this new mission. She quickly discovers that willingness isn't the problem; the Hands and Voices want to join, but they want full equality in their membership--including the ability to attend council meetings in person. Amid the sunshine and surf of the tropical, idyllic planet of Song, it seems the biggest hardship Xandri and her friends will face is the task of re-rigging a spaceship to carry creatures the size of killer whales.

Then the Last Hope for Humanity arrives, and this time they've brought an army.