In the land of Erin, a young girl named Aria lives all by herself in a large tree house within a beech forest. Though living without the company of her dear grandmother, Ganeida, for the first time is lonely, Aria has no problem handling things, even with the coming winter bringing heavy snowfall. After all, even though she cannot cast a single spell, she is a witch, with natural apothecary and cooking skills to make up for her magical deficiencies.

As a witch, the sudden appearance of a large white wolf that can speak does not surprise Aria as much as the average person. But what does is the wolf's request to shelter him for the winter—and perhaps for even longer, as the two become fast friends and Aria lovingly names him Gwyn. Their friendship marks the beginning of Aria's exploration of the world beyond her forest—opening up a myriad of possibilities for the sheltered witch to experience and make even more friends along the way.