Literary agent Comrie Melrose and his strong-willed fiancÃ‰e Hera Camden meet some odd fellow hikers on their Scottish walking tour--which begins to flounder (as does the engagement) even before Comrie stumbles on a dead body in the fog. Comrie refuses to report the corpse to the police; then, back in London, at a reunion party for the hikers, he trips over another corpse--this one belonging to boorishly convivial Neville Carbridge, whose boring buffoonery seems to have gone too far for someone. And red herrings abound, with bared secrets and false arrests, before psychiatrist-sleuth Dame Beatrice Lestrange Bradley (The Death-Cap Dancers, etc.) is clumsily dragged into the case, making the obvious connections that reveal the killer. Despite the fragile plot and motivation: a modest upturn for veteran Mitchell, whose struggle to be au courant has its own kind of old-fashioned charm--with solidly well-drawn characters (including prim male-chauvinist Comrie).