Everything on the Nova Scotia coast exudes danger and malice when the MacEwens arrive for Dad's summer of seabed-research--and Jeannine (about eleven) learns that somebody on the research-team is leaking information to the Russians. Will there be a second, parallel ""collision,"" as her mother warns, between Jeannine's intuitiveness and her father's insistence on hard fact? (""A dark and terrible war under the sea. . . up here. . . ."") The thriller-scenario is overloaded with lurking, scheming oddballs, mysterious finds, local superstitutions, and natural hazards. The interface with Jeannine's apprehensions and exertions--the bear-shaped offshore rocks that ""roar"" their warning, the malign ""Prophet""-rock she's warned against--is sheer juvenile-gothic hocus-pocus. She and her siblings do, however, have some individuality: logical, inquisitive Andrew, in particular, is an effective foil/accomplice for fancifying Jeannine. And the wind-up does roughly balance the scales: Jeannine, in defiance of all warnings, almost loses her life at the Prophet rock--but she also proves her father wrong about which of his two suspicious associates was doing the spying. Murray has a feel for the coastal setting, and the children's mixed response to it. But the conflict between Jeannine and her father is neon-lighted and the plot is maladroit melodramatics.