The Samhain Soldier. Cloudburst Colorado, #7

It's all fun and games until a tracker demon comes for you... Phinnius Winterbourne, a soldier in the Summer Court of the Sidhe, has inherited his maternal grandfather's sword. But the Winter Court of the Sidhe now wants it and him. Seeking help from his older brother seems like a good idea, until he runs into a witch. And the tracker demon sent to fetch Phinn. Not a great day. Kendra MacGillivray is preparing her altar for Samhain when she runs head-on into Phinnius and his problems.
She doesn't have time for the arrogant fool who has irritated the Fae. When her healing spell clashes with that of the tracker demon, they end up in the Sidhe realm with no way home and a tracker demon familiar. Every witch needs one. Trapped in the Fae realm, they must work together to keep the sword out of the Winter Court's reach and get back home again before Samhain, when the veils close for the year.
Nothing is as it seems and Phinn's family secrets may break everything-him included. If they don't protect the sword, they could lose more than a family heirloom-they could destroy the world. No pressure.