The Tree & the Egg - Arcana Glen Major Arcana Series, #12

Welcome to Arcana Glen, a tiny mountain town in Colorado that holds a real castle and a secret... it's the Portal to other Spheres of existence, where magic is real. Over the past year, the Twenty-Two Guardians, who each represent a power of a Major Arcana in the Tarot, have finally all been Called by the Light to serve. Furthermore, each of them have found their soulmates. The eleven couples are now ready to stand against the Dark Triad's plans to conquer all the Spheres.  However, the Seeress has had a Vision that one of the Guardians is a Traitor.
That not only puts the whole Tree of Worlds in danger, it means one person's true love is false. Note: All the other books in the Major Arcana series can be read independently, although they are probably more enjoyable in order. However, this is the conclusion of the series that finally answers the question--who massacred the former Guardians ten years ago? And will that hidden enemy succeed in annihilating the Guardians again?