I'm a huge fan of everything Martha Wells has written, in large part because her female characters are always so well-developed and presented as strong individuals, not just an afterthought to a male-driven plot. The Wizard Hunters
is the first volume of a trilogy - the first time Wells has presented a multi-volume work (for which I am grateful, having gotten fairly sick of fantasies that contain about one book's worth of substance, but are stretched to fill three -- or more.)
Tremaine Valiarde is the daughter of Nicholas and Madeleine Valiarde, who were the main characters in Death of the Necromancer
(set in the period prior to Tremaine's birth.) As TWH
opens, Tremain's mother is dead, and her father presumed so after his disappearance. Tremaine herself, an author and playwright, has been living alone in the family home, Coldcourt, wrestling with a bout of depression, and volunteering with the Aid Society to help the victims of the current war (although in truth she seeks simply to place herself in a situation to bring about her own "accidental" death.) A previously-unknown enemy, called the Gardier, assaults not only the people and buildings of Ile-Rien, but also the magical bulwarks that shore up its defenses, as well as its armaments and any other technology they might try to use.
Tremaine gets dragged into an investigation by Ile-Rien's magicians when they seek to borrow a device made for her as a toy by her "uncle" Arisilde Damal, Ile-Rien's greatest magician, who is also missing and presumed dead. Unfortunately, the sphere refuses to be employed by anyone unless Tremaine is present, and her death wish gets set aside as she and several others involved in the project -- to find a way to counteract the Gardier spells and give the military a fighting chance -- unexpectedly are transported to a different world where, with the help of allies native to that world, they might just find a way to undermine the efforts of the Gardier to destroy their beloved country.