In the serpent's wake

Tess Dombegh joins Countess Mardou's sailing expedition as an undercover spy for the Queen to prevent war, but she is more concerned with finding the last World Serpent, the Polar Serpent, to use its magical healing abilities on her best friend Pathka. When someone from Tess's painful past returns, old wounds threaten to jeopardize the mission. Meanwhile, unbeknownst to the people on the ship, another expedition led by Spira, a dragon Tess wronged in the past, tries to be the first ones to the Polar Serpent to execute its own plan.