When Jack Colby hears the voice of his former wife Eva on the phone he fears the worst - and he is right to do so. The body of her husband, Mexican band leader Carlos, has been found on the towpath of the River Medway and Eva becomes the chief suspect. Car detective Jack goes into action - although he is hindered by a second case, as the beguilingly beautiful twenty-year-old Daisy is determined that his efforts should be devoted to finding her stolen...