Plummergen village folk are keen as mustard to beat neighbouring Murreystone and win the Best Kept Village competition. Art teacher Miss Seeton is asked to create some Before and After pictures, showing residents of The Street how to improve the look of their houses. Yet one of her sketches is worrying, showing her own cottage, Sweetbriars, amidst billowing smoke, all too reminiscent of the current spate of murderous arson being investigated. Then another, that looks at first like a cosy Wind in the Willows scene seems to hint at something very dark lurking in the shadows . . .
Serene amidst every kind of skullduggery, this eccentric English spinster steps in where Scotland Yard stumbles, armed with nothing more than her sketchpad and umbrella!