When veteran British suspense-man Gilbert isn't writing witty murder-mysteries (The Black Seraphim), sturdy police-procedures for Petrella, or espionage bits for Calder & Behrens, he turns to neat chase-thrillers involving innocent bystanders--and this agreeable caper is one of them. John Benedict, 42, has become independently wealthy by developing and then selling his own electronical-engineering firm in London; he's headed back to his native New Zealand after 20 years away--when an impulse causes him to leave his charter-flight in Rome and simply wander through rural Italy, fixing trucks and tractors in exchange for room-and-board. But this footloose idyll turns to deeper involvement when John--calling himself Signor Gabriel--stops for a while with the endearing Paolis: vigorous Grandma P. runs the farm; her son Ermine is a foreman at a big factory nearby, owned by the MBA conglomerate (the very one that bought John's flexible-disc business); Ermino's beautiful daughter Anna works in the office there. (On weekends everyone does farm labor.) And John, while chastely falling for Anna, soon learns that union-leader Ermine has been threatening to expose some shady doings--including Mafia dealings--at the MBA factory. Then--sudden tragedy and feverish flight: all the Paolis perish in a Mafia-engineered fire; John survives but must flee north on foot through the mountains--nearly dying of exposure, finding some monastery sanctuary, eventually crossing the border into France. In Nice he finds an ally: former secretary Monica, on a vacation from her new job at MBA. He hitches a ride to London with trucker/smuggler ""Midge,"" a Dickensian charmer with domestic problems. And eventually, after learning that he is ""presumed dead"" (that flight to New Zealand had a fiery crash), John adopts a new identity to wage a war of vengeance against ruthless MBA. . . though there'll be a few sad casualties before justice triumphs. The basic scenario? Fairly ordinary, without a doubt. But John's a modestly likable hero, the supporting cast is distinctive (including the no-nonsense love interest provided by Monica), and Gilbert keeps everything moving along at a crisply professional pace.