Harry Caines has a ruffled and unsettled team. The validity of his methods has yet to be proved. Time will tell, but right now there's word that Krugerrands are changing hands at a local casino. Caines suspects smuggling, but how to prove it. And what's worse - Tom Gibbons is implicated.

Caines asks Alyson to join the Road Fuel Testing Unit for a few days. So instead of the Custom-House long room, it's field and farmyard and getting to grips with members of the farming community. A celebration gives Caines a chance to relax with his team.

Caines and his team look into the complexities of the ice-cream trade, where skirmishes between two local firms seem about to explode into open warfare. An invitation to Harry Caines takes him into the home of a French businessman who Calvin suspects is up to no good.