Cherished By Her Guardian (Yuletide Shifters Book Three). Yuletide Shifters, #3

Well of Magic Guardian Declan Knight has spent the last nine years protecting the world's source of magic from Jack Frost and his evil followers. As it draws close to Christmas Day, when Santa will be at his lowest power and most vulnerable, wolf shifter Declan can't afford any distractions because they could cost the magical people of the world everything. Winterlyn Brooks has never been able to shift into her arctic fox, despite her parents being alphas and coming from a long line of strong and capable shifters.
Without access to her shift, she'll never find a male who will take her for a mate, and getting left out of everything with her people is wearing thin. When an online search suggests she could get help with her shift at the Well of Magic, she finds a witch willing to take her there. But the witch has an agenda that isn't exactly altruistic, and not only does Winterlyn find herself in the middle of a battle between good and evil over control of the Well, but she also finds her truemate in the snowy land at the top of the world.
Can she and Declan keep each other safe while Santa and Jack Frost battle for dominance, or will their relationship be over before it starts?