Belor lives and she's out to destroy the Nidus. Once again, Rothgo needs the children's help to defeat Belor. This time, they go to Asgard.
The Nidus has broken into five pieces, and the children must find them before Belor can. Their first stop gets them and Rothgo involved in the plot to assassinate King James I.
Having secured one part of the Nidus, the children find themselves in America. Rothgo, as a medicine man, has lost his memory and the children are taken in the besieged fort of Davy Crockett and Colonel Bowie where Belor is at work.
With two parts of the Nidus already found, the children arrive in ancient India with all its mysticism and magic. Belor appears as the multi-armed goddess Khumbakarna to foil Rothgo as Prince Sagara, who is due to be married.
Deep in the sewers of Victorian London, the children encounter an unusual sleuth, T.J. Shadrach, the victim of a spell by Belor to change his face to that of Rothgo as the detective tries to foil a theft of the crown jewels.
Transported to the Great Siege of Malta in 1565, the children encounter Rothgo in another extraordinary disguise, that of Sir Hugo, an old knight who, with La Valette, tries to keep the Turks at bay.
The children look for Rothgo in ancient Egypt at the time of Tutankhamun's burial, and seek a final desperate solution to Belor's evil powers. The children are accused of being grave robbers though and taken before Princess Mertaten.