'King,' they said, trying out the word, 'Osro is King. 'Now, stand up,' Osro said. 'Take me to Susan's door. You are my hands and I am your head. Soon O will be ours.' For Susan and Nick the adventure at last seems at an end. They are leaving the magical land of O, the scene of The Halfmen of O and The Priests of Ferris. But even as they prepare to step back to Earth, strange and evil forces reach out to ensnare them. For Susan and for the Motherstone there is one final, frightening task. Motherstone is the last thrilling book in Maurice Gee's saga of the world of O.