It features the transition by Killashandra Ree, a young woman who has failed as an operatic soloist, to the occupation of "crystal singer" on the fictional planet Ballybran.
[6] DuPont transferred her husband temporarily to Düsseldorf, Germany, in 1962/63, where Anne resumed vocal training[7] but suffered a crisis when she was informed that a flaw in her voice would limit her in that avocation.
[8] McCaffrey divorced her husband in August 1970 and emigrated to the vicinity of Dublin, Ireland, in September with her second Dragonriders of Pern book nearly finished and a contract for the third.
[9] The markets for children and young adults provided crucial opportunities, as when editor Roger Elwood solicited contributions of short genre fiction to anthologies.
"Milekey Mountain" was adapted in comics form (artist uncredited) in the 1979 publication Questar: Illustrated Science Fiction Classics (Golden Press, ISBN 0307111970).
At the spaceport she meets a vital, older man who uses perfect pitch, and his occupational experience as a "crystal singer" on Ballybran, to identify an incoming space shuttle on the verge of explosion.
He treats her to a whirlwind romance and the experience of her home planet in ways entirely unknown to her, but sincerely warns her against the high-status, high-income occupation that makes such a vacation possible for him.
Further, one of its occupational hazards leaves him in a coma, but Killashandra determines to accompany his return home under life support, and to investigate membership in the Heptite Guild of crystal singers for herself.
Some newcomers will die of the initial infection and many will adapt only partly, with a mix of permanent symptoms such as vastly increased visual acuity along with complete deafness.
Full adaptation brings remarkable benefits, including increased sensory perception, rapid tissue regeneration and a vastly prolonged life expectancy, but it renders all hosts sterile, and eventually causes severe memory loss, paranoia and dementia.
The Guild provides life support for physically disabled or insane members, many aspects of the industry are highly centralized, and everyone begins with big debts.
The cost of a black crystal set is high, even on the planetary scale, which has made its acquisition politically controversial and its installation a celebrity event.
The Guildmaster offers her an opportunity to travel to the music-loving planet of Optheria to install a set of Crystals on their damaged Crystal-powered organ in time for their upcoming Festival, an easy task that will allow Killashandra to clear her debt and escape the storms.
Killashandra confirms that the Optherian leaders effectively forbid unhappy citizens from leaving the planet, in violation of Federation law, and that they use the Crystal organ to transmit highly illegal subliminal hallucinations to the population at the seasonal Festivals in order to keep them compliant.
The islanders, who are less influenced by the subliminals, made a plan to destroy the organ, then kidnap the Crystal Singer sent to repair it, creating an interplanetary incident that would demand a full investigation.
At an automated trial, Killashandra speaks in Lars' defense, but when stress monitors misread her concern for him as fear, the computerized judge believes he has threatened her and finds him guilty.
Lars tries to tempt her away from the Ranges in hopes that time away from Ballybran will forestall the inevitable, but Killashandra holds out for one good cutting to pay off their considerable debts, risking their lives in the process.
Finally Guildmaster Lanzecki gives Lars and Killashandra an off-planet assignment to investigate a recently discovered entity: a giant liquid crystalline mass termed "Jewel Junk".
Returning to Ballybran early, Killashandra finds Lanzecki, her former lover, has gone into the Ranges during a fierce sonic storm that kills him, leaving Lars the new Guildmaster.