Plum and her companions investigate a club who went deep underground and into a safe. Meanwhile people begin transforming into monsters and a mysterious gas may be behind it.
August and Melody continue their adventures as they search for traces of the Master's whereabouts, trying to save Olenier from the threat of his secret army. After months of training they have become better equipped to take on such a task, but there are still many mysterious dangers that lurk within the shadows around them.