Tooth Fairy Pixie is sent to a new territory in Pennsylvania when her boss calls in a favor. On her nightly rounds of collecting teeth from little sleepers, Pixie's quiet mission goes awry when she accidentally falls out of a window, only to land in the strong arms of a polar bear named Hunter.

Hunter was with his clan for a celebration and thought someone was breaking into one of the homes. He quickly discovers the would-be thief is a tooth fairy—and also his truemate.

While Hunter and Pixie explore their newfound bond, trouble brews in Northernmost. Santa has enlisted a secret ally to prepare for a confrontation with his brother, Jack Frost. When Frost's second-in-command strikes at the heart of Santa's operation, it's up to Hunter and the Yuletide Guardians to step in and save the day.

As magic and romance collide, can Hunter and Pixie stop Frost's plans and protect the world's magic, or will all be lost on Christmas Day?