The family firm of auctioneers finds itself threatened by all sorts of outside interests. Big firms encroach on Caradus's territory and at the other end of the scale are the knockers. The "knockers" and a big-time auction firm threaten to put the House of Caradus off for good. It begins with the "knockers" (house-to-house callers who force owners to part with their treasures at low prices) picking on Mr Croft, an old friend of Helena's. Croft turns to Helena and she promises to keep a lookout for the items, among them a pretty Worcester figure of a girl in a blue dress. Things look bleak when Lionel gets news that Blofeld, a London auction firm, is moving  into Chester to conduct an antiques surgery whereby people could bring their valuables for evaluation. Thus Helena, Lionel and Victor plan to discredit Blofeld before it can establish itself and take away some of the Caradus business.