Blood Bonds by Jasinda Wilder

Maeve Sparrow is a prisoner.

Deep in the bowels of The Immortal Tribunal’s secret headquarters inside a mountain in the Swiss Alps, she’s bound, without magic, and cut off from her bloodmate Caspian and her coven—Alistair, Phineas, and Stirling.
Will they experiment on her? Simply execute her? Lock her up and throw away the key? She’s not willing to stick around and find out.
With only her wits, courage, and nerve, she is determined to escape her cell and return to Caspian—and the cause she believes in more passionately than ever.
She finds two allies in the most unlikely of quarters: the very wolf Shifter who brought her mage-cuffed and kicking to her mountain prison in the first place, and her grandfather, Elias Sparrow, the powerful fae male responsible for Maeve’s very existence.
Along the way she discovers new depths to her abilities, a renewed determination to overthrow the Tribunal once and for all, and maybe even a whole different kind of bond with a certain tall, growly, sexy alpha wolf.
Maeve Sparrow is no ordinary immortal, and with every passing day, it seems like the future of all immortals—and maybe human civilization itself—is bound to Maeve’s fate.
She’s just not sure if she’s equal to the task. Good thing the men at her side believe in her, even when she doubts herself.