Although equipped with fine adoptive parents, a nice apartment and job, and a blueblooded almost-fiancÃ‰, 28-year-old Katherine Derwith decides to advertise for information about her unknown true parents--a step which unleashes one of veteran Johnston's likably unlikely plots. As Katherine will soon learn from Carl Dietrich (who answers her ad), the story goes like this: Katherine's real father, Michael Russo, was a young Italian mountain-shepherd who was an accidental witness when Nazi Wilhelm Dietrich (Carl's late father) murdered six men and hid a treasure in an abandoned iron mine; Katherine was abandoned when her terrified widower-father was recognized years later in N.Y. by Dietrich's ruthless confederate Hans Gorman (who will stop at nothing to learn the treasure's location). Now, however, Dietrich is dead, and son Carl (who implausibly has total recall of conversations overheard at age nine) is eager to help Katherine--and she does indeed find her father: he never really lost track of her, it seems, though he's now dying of cancer. But evil Gorman is still after that treasure; and one of his henchmen fatally pummels Dietrich's widow Inga--who, before expiring, manages to give Katherine a map pinpointing the secret mine's location. So it's off to Italy for Carl and Katherine, with Gorman in hot pursuit, love blossoming, and happy endings all 'round in the end. Johnston fans won't be surprised to find a cardboard cast of characters--but they'll also get the reliably bouncy plottings of an old hand; overall--a bland, sturdy known commodity.