Traces the life and work of the Irish artist, book illustrator and stained glass artist Harry Clarke (1889-1931) with major contributions from his biographer Nicola Gordon Bowe as well as many stained glass artists, poets and historians. The film takes the artist's work in stained glass, which was mainly religious an ethereal, and in book illustration, which was mainly dark and fantastical, as the basis for its title and tells a story of talent, struggle, success and the censorship of his final masterpiece 'the Geneva Window'. Harry Clarke brought his expertise in working in fine decorative detail in glass to his book illustrations, most notably in the tales of Hans Christian Andersen and Edgar Allan Poe where he is compared to Aubrey Beardsley and which are featured in the film and paralleled with German Expressionist cinema of the time.