Emily and Navin's mother is still in a coma from the arachnopod's poison, and there's only one place to find help: Kanalis, the bustling, beautiful city of waterfalls. But when Em, her brother, and Miskit and the rest of the robotic crew aboard the walking house reach the city, they quickly realize that seeking help is looking for trouble, dangerous trouble.The Elf King's son, Trellis, is still after them, but this time he's accompanied by a mysterious...

Navin journeys to the city of Lucien where he searches for a beacon essential to his fight against the Elf King; while Emily heads back into the Void with Max, one of the Elf King's followers, where she learns his darkest secrets.

As the Elf King makes new amulets that will give him power to destroy Windsor once and for all, Emily and her friends desperately make preparations to defend Cielis in what will inevitably be a brutal war, hoping that it will be enough to defeat the Elf King.

"After her confrontation with Ikol, Emily finally understands the stone's power and what she must do to defend Alledia from the shadows. As she travels to Typhon to help her mom and Navin, Prince Trellis returns to the Kingdom of the Elves to save his countrymen -- and confront the fraud who has seized power in the absence of a king. The threat of darkness follows all Stonekeepers closely, and it will take the strength of both new friends and old...

Emily and her brother Navin head for Kanalis to find an antidote for the poison that is killing their mother.

"Emily, Trellis, and Vigo visit Algos Island, where they can access and enter lost memories. They're hoping to uncover the events of Trellis's mysterious childhood -- knowledge they can use against the Elf King. What they discover is a dark secret that changes everything. Meanwhile, the Voice of Emily's Amulet is getting stronger, and threatens to overtake her completely"

Emily and her brother Navin head for Kanalis to find an antidote for the poison that's killing their mother.