Angus Macbain and the Agate Eyeglass — Angela Townsend

When Angus MacBain finds that a Sea Hag has cast a deadly spell on Vanora's father, he must once again set aside his life in the outside world to plunge into danger to save his friend's father. But when he seeks out Fane, advisor to the MacBain Kings, Angus discovers that Vanora's father is not the only one in dire peril. Now with two souls in mortal danger, Angus and Vanora must face the unknown challenges of Fingal's Cave alone this time―without the aid of his trusted advisor. But what new and dreadful dangers lurk in the Hall of Kings? Armed with only the ancient weapon of the MacBain Kings, the heirloom amber eyeglass, Angus is about to find out.