Susan had always been a bit odd and never really got on with her cousin Nick, but the mark on her wrists draws them together in a frightening adventure. They are summoned to the land of O in a desperate attempt to save the planet from cruel Otis Claw and the evil Halfmen.
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Used availability for Maurice Gee's The Halfmen of O
September 1982 : UK Hardback
October 1984 : UK Paperback
October 2005 : Australia, UK Kindle edition