An unkind satire on the inadequacies of the British secret services, between the wars, within whose ranks Compton Mackenzie served. The plot involves His Majesty's Director of Extraordinary Intelligence - M.Q.99(E) - sending British agent Major Arthur Blenkinsop to counter the interference of the wily Burgundians and Venetians in the affairs of Mendacia. Blenkinsop also has to deal with the dangerous American agent Katzenschlosser and the charms of the alluring Senora Miranda.