In a country mansion converted to adult educational courses, Mr Utamaro is lecturing on Zen Buddhism to a small and not entirely appreciative audience. But Zen questions and their seemingly quirkish answers predominate, until they are superseded by two of greater urgency: ''Who stole the wakizashi?'' and ''Who killed Flaveen Mills?''

H. R. F. Keating provides the solution in the same brilliantly humorous vein which won him so many admirers with his first novel, Death and the Visiting Firemen.