The Secret of the Willowdeer is the third Proposed Serial of Spectral Shadows. It is preceded by Serial 2 - The Aslanders and succeeded by Serial 4 - The Trouble With Paradise. This serial is currently not in the works, and the only material available is the summary from the Synopsis Page.
The synopsis is as follows:
Jonathan and Raelian go on an adventure to help their friend Beau discover the truth about why he was abandoned after his birth. The journey also promises to reveal to their cousin Clarice what became of her older brother, Nicolas.
The Willowdeer pretend to be friendly, but are secretly planning to sacrifice the travelers to bring about the resurrection of Salocin, whom they believe will give them power and dominion over the forest world.
But eventually Clarice gets her wish and discovers the truth about Nicolas, only to find herself at risk of falling victim to his deadly curse.