Plum and her friends are traveling to the misty Bokati Island. There they will study with the mysterious Guardian Master Em, who is the keeper of the ancient forest there. The field trip comes just in time for Plum, who still can't figure out why she's so different from the other Novices on Lotus Island.

At first, Plum doesn't know what to make of this quiet and sometimes gloomy place. But it doesn't take long to discover that Bokati is brimming with an incredible array of fascinating animals and plants.

When an unseen force begins to destroy the trees, putting the entire ecosystem at risk, Plum and her classmates must spring into action. Plum is determined to help, even though she's hiding secrets about her own Guardian powers from even her closest friends.