Spark of Fate by Allie Blake

A spark shall blaze at fate’s design…

The veil between realms is always thinnest on Samhain. Olivia—plagued by nightmares and desperate to leave her small village—is led astray by a mysterious force. Dropped into the realm of Faerie, she has no way home. When one of the vicious Unseelie Fae of legend crosses her path, the two become reluctant allies.
Together, they embark on a journey, encountering obstacles that unearth secrets long since buried, leaving Olivia with more questions than answers. The more she learns, the more secrets are revealed and betrayals uncovered.

Because when it comes down to it, who can she really trust?