The Healing Stone oleh Vacen Taylor

After finding the Silvershade and escaping the attacking forces as the Wilder Forest city was scorched to the ground, Mai, Akra and Kalin must now face the evil that has consumed Long. 

When they reach the land of Cruscar and enter the ice city of Algus, the children are confronted with an ice challenge to win an audience with Queen Isolda. A treacherous journey now awaits them if they are to reach the Healing Stone to save Long. 

But Piceptus, the underworld king, will not give up his search and he will do anything to bring the pilgrims' journey to an end. The children grow stronger as they begin to master their powers, but will this be enough to escape this danger and continue on their pilgrimage to fulfil the prophecy?