Peter Dickinson's stories have a way of settling around you, so that when thirteen-year-old Jake is disclosed to be blind, the news seems simply to confirm his extraordinary powers of observation. And it is these powers--aptly, the ability to ""see"" in the dark--that will safeguard Jake and older brother Martin when their ghost-hunting grandfather disappears. Martin has just put his savings into a BMW bike--better that, Jake decides, than the Green Revolution Defense Fund--and on their half-term holiday the brothers head for Newcastle where Granpa was last inquiring after apparitions to explain away. Oddly, he has always been a presence to Jake--a comforting, ""protecting intelligence."" But, pursuing the mystery of Annerton coal pit, he stumbles upon a sinister true-life intrigue, and the boys fall in behind him. This has to be a Green Revolution job--as Martin is of course the one to discover--so that the issues shaping up en route can be aired. Like not only being willing to die for a cause but, as GR leader Andrews explains to the anguished Martin, ""to kill for it."" Or, on Martin's part, to denounce its agents in order, hopefully, to save the cause. But meanwhile the three are trapped in Annerton Pit, and it's the devil's own cave to escape from, with something present even rational, home-in-the-dark Jake can't shake. Until, within him, the dark lifts . . . The exorcism of Jake's ghost entails prolonged groping about, literally and figuretively, and the analogy between the pit's terror and political terrorism--both extinguished by a mine detonation--is forced upon the reader. But this intelligent, literate, thoughtful thriller--so intrinsically a blind child's experience--is worth having on any terms.