Rendell's favorite psycho-suspense technique--two separate plots that crisscross ironically, often fatally--resurfaces in this new, intriguing, yet very disappointing thriller: a long, low-key tease that never really rewards the reader's trust and patience. In one half of the novel, we meet 14-year-old Mungo Cameron, a likable, gawky lad who's one of the key players in an elaborate spy-game being carried on at two rival English "public" (private) schools--complete with codes, "drops," "safe houses," defectors, and double-agents. Currently, in fact, Mungo (chief of "London Central") has begun to wonder if smooth, sly, pretty Charles Mabledene, a recent defector from "Moscow Central," is perhaps a double-agent. (Is it Charles--or a mole within Mungo's elite circle--who has been leaking secret codes to Moscow Central?) Meanwhile, in the novel's other half, we meet 40-ish garden-nursery owner John Creevey, who's devastated by the desertion of his wife Jennifer: she has left him to reunite with the great love of her life--a creepy, sophisticated layabout named Peter Moran. John pleads with Jennifer to reconsider; he digs up the nasty secrets in Moran's past (arrest and conviction for molesting a young boy). But Jennifer remains intractable, begging for a quick divorce. How, then, do the two plots intersect? Well, John has stumbled onto the coded messages which Mungo leaves beneath a highway overpass for agent Charles Mabledene; fascinated, he has decoded some of the messages--and has decided that they must be part of a dangerous mob's drug-traffic schemes! So, increasingly unhinged and hoping to somehow harass (or worse) his rival, John puts a fake message in the spy-game "drop"--one that orders Charles to tail Peter Moran. And young Charles, who just happens to be the sort of pretty lad Moran dotes on, sets out to perform this mission brilliantly, determined to prove his loyalty to London Central. There's a grim, violent denouement to come, of course, but only after an attenuated buildup--and only involving supporting players. Loose ends abound, since Rendell has lumbered neurotic, repressed John with excess psycho-baggage: a loony best pal; a bonkers employee; and memories of a murdered sister (who might have been a secret nymphomaniac). Finally, then, despite fine atmosphere, dozens of clever touches, and considerable charm in the schoolboy-espionage, this is one of Rendell's least effective constructions: too much contrivance, too much clinical psychology, too little genuine passion or peril.