Althea Vestrit is the younger daughter of Ephron Vestrit and Ronica Vestrit, younger sister of Keffria Vestrit. When we first meet Althea, she is a willful tomboy but through trials and adventures she grows up and learns more responsibility.
After the Blood Plague kills the three Vestrit sons in their youth, Ephron Vestrit sees fit to make Althea the heir to his liveship Vivacia. For all intents and purposes, Althea grows up on the Vivacia and fully expects to be named its captain upon her father's death. Instead, no sooner has Vivacia quickened then Althea finds Ronica has given Vivacia to Keffria's husband Kyle Haven. Kyle, a Chalcedean who believes women have no place aboard ship, removes Althea from Vivacia and installs his son Wintrow Vestrit, whose schooling as a priest Kyle has interrupted for this purpose.
Kyle also removes Ephron's first mate Brashen Trell, a social outcast who Ephron redeemed, from Vivacia's crew, and soon makes his plans known to make Vivacia a slaver, to Althea's and the rest of the family's horror, as a liveship will not tolerate so much human suffering. Keffria and Ronica begin to question their course to install Kyle as captain, despite Kyle's assurances he will treat his slaves gently.
Althea is a longtime friend of the liveship Paragon, who she first met as a little girl.
Althea is petite and slender, and bears a striking resemblance to her nephew Wintrow. She has dark hair, skin rather tanned from much time aboard ship, and wears a wizardwood charm shaped like a skull at her navel to prevent conception.
After Kyle kicks her off Vivacia, Althea vows to get her ship back. She flees home and with help from Amber disguises herself as a ship's boy named "Athel Vestrit," and works her way through a voyage on a seal-hunting ship, the Reaper. On that voyage she meets again with Brashen, who does his best to protect her and to help her be a good sailor without being obvious; there is tension between them as well as friendship. She proves very efficient at skinning the animals and packing the meat, and wins the respect of the captain.
When at the end of the first voyage Althea asks for her ship's ticket and reveals her true identity, the Captain kicks her off the ship without pay for her deception, and for being a woman.