Binding of Silver - Blood of the Fae, #3

Lies, labyrinths . . . and lost souls? Never bargain with the fae. The society of Byren lives by this rule, but it's one herbalist Jessa Caldwell has broken time and again. So far, she's escaped unscathed, but her sister Ainslie-snared in a bargain she can't recall making-doesn't share her good fortune. After Ainslie vanishes into the night, Jessa fears the horrors her sister might suffer. She's witnessed what fae do to mortals-using them as playthings to torment, even transforming them into monsters.
No matter the cost, she's resolved to find her. But she soon learns that Ainslie isn't the only one missing. All across the kingdom, mortals are disappearing without a trace. With the aid of fae arbiter Riven and kit-isne Jade, Jessa seeks those responsible, but as she does, her actions draw unwelcome attention from all quarters-fae and mortal alike. Even those within her own home mistrust her purposes, and she risks shattering the relationships that mean the most to her. Yet she cannot abandon mortals to the mercies of Other.
Her quest for answers takes her through the heart of a labyrinth and into the dangerous midsummer hunt of the fae, where the creature they seek could claim her life as swiftly as the fae will if they ever discover her true purpose. She'll need everything she's learned about fae-and her own nature-if she's to have any chance of surviving the maze of hidden truths and shifting loyalties around her.