Blat (an unfortunate name for a singer) is a young farmer boy recruited by the Minstrels' Guild. Fourteen years later, he has completed his studies and been a Touring Minstrel ever since. Blat needs material for a new song and follows clues in an ancient text. While travelling near Whitecap Island's glacier, silent assailants herd him into a cavern within a mountain. He stares at the colossal cylinder of rock occupying one end. Their leader, Quirindi, explains that her people maintain the machines which invigorate the cylinder. The cylinder in turn gives them long life, mind-to-mind speech, and brings light to Station One, the name of their home. But they are failing at their task and her people are dying.
He recruits Crag Bithoone, a brilliant but unstable scientist. In their search for answers, Blat is captured by the Brothers of the Watch, a sinister cult that uses telepathic power to control and punish. His mind is brutally tortured forcing his consciousness to flee into a tiny part of his brain where he cocoons himself within layers of music. When he revives, a woman encased in stone ensorcels him into destroying the cylinders which hold her captive. Blat struggles to resist - the cylinders are what the Stationers need to survive - but she is too strong. While the Station crumbles around them, she touches a map of Whitecap Island and disappears. Blat puts his finger on the same place... and is transported to a desert. He is once again taken by the Brothers and forced through an invisible barrier concealing a vast stronghold and joins hundreds of prisoners compelled to polish cylinders. On a gallery at one end of the underground cavern stands the stone woman, Mir.
Blat believes that music can block the Brothers' mind control and composes a simple song to teach his fellow captives. If the song does not work, the Brothers' plan to subjugate Whitecap Island will be unleashed at the dark of the moon. And where was Crag?