The ""Jubilee Mysteries"" pick up some steam--and a touch of class--with this murder-less but suspenseful London tale of ""proper"" folks who give crime a try. Ad-man Vyvyan Weighman is ""starting to come unstuck as a money making machine,"" and his late, rich father's will leaves him zilch, so he persuades livein girlfriend Barbara to join him in a bank-heist ""perfect crime."" She is to inveigle herself in as au pair in a country bank manager's household, charm him, and maneuver him into precisely the right spot for having his keys lifted. All goes exactly as planned--except that Barbara's toy gun gets left behind. How the coppers trace the gun to her antique shop, how she's blackmailed by the shop-owner, how Vyvyan goes to seed from sheer fear--enough tense, plausible turns to keep the London streets and country roads whizzing by.