Tess is on a double mission: to get her friend Pathka to the Polar Serpent and save his life; and to observe Ninysh aggression against the indigenous peoples of the Southern Archipelagos and report it to her queen.

Other viewpoint characters include Spira, a dragon scholar who bears a justifiable grudge against Tess; Countess Margarethe, who must figure out how to use her power for good; Hami, a world-weary Ggdani Watcher who just wants to get home; Kikiu, a quigutl who knows she’s special and is waiting for the world to notice; a Katakutia, a mystical being who understands all languages and has no name; and Jacomo, a seminary drop-out who thinks he’s lost his faith but maybe hasn’t, quite.

Tess realizes that if she really wants to make a difference to the island peoples, she needs to go back home and take on the unglamorous task of shaping the next generation of leaders, her nieces, Zythia and Verica.

If Tess of the Road was about re-learning how to be the protagonist of your own life, In the Serpent's Wake is about taking that insight out into the world and applying it, not by swooping in to save the day like a superhero but by setting your ego aside and asking what others need of you.

"[4] Booklist gave In the Serpent's Wake a starred review, writing "Each of Hartman’s nuanced characters—Tess, Margarethe, Jacomo, Spira, and more—grapples imperfectly with the injustices they observe, doing the emotionally difficult work to move from ignorance or denial to acknowledgement and action.