A Christmas tree lot. Mysterious string lights. A most festive secret.

It's the holiday season and Molly Green, the manager of Patty's Plant Place, is busy selling fragrant firs, teaching holiday crafting workshops, and eating all the holiday desserts. But when mysterious string lights appear on Christmas trees for sale at the garden center, she can't help but wonder who snuck through the fence to create such festive mischief.

With the help of her twin sister May and their quirky crew of employees, Molly sets out to solve this cheerful mystery. Will she untangle the mystery of the twinkling lights before snow blankets the ground—or will the secret remain hidden among the Christmas trees?