Ice CrownAndre Norton
science fiction, young adult
Offlas Keil and his niece, Roane, had their orders: to land on Clio and search out its treasure.
Clio was a closed planet. Settled centuries ago as a Psychocrat experiment, its colonists had been brain-cleared, implanted with false memories - and conditioned to obey.
Keil and Roane touched down at Reveny, one of Clio's more archaic kingdoms. Roane didn't know it at the time. but she was to form an alliance with Reveny's Princess Ludorica in a search for the greatest treasure of all - the strange, the mysterious, the all-powerful ICE CROWN.
Andre Alice Norton (1912-2005) was an American science fiction and fantasy author (with some works of historical fiction and contemporary fiction) under the noms de plume Andre Norton, Andrew North and Allen Weston. Norton published her first novel in 1934, and was the first woman to receive the Gandalf Grand Master Award from the World Science Fiction Society in 1977, and won the Damon Knight Memorial Grand Master Award from the Science Fiction and Fantasy Writers of America (SFWA) association in 1983.
Andre Norton. Wikipedia.