It is another exciting Mary Eliska Girl Detective whodunnit, with less romance than usual. The plot is that a couple had a room in which all walls and items are white. One day when they were away, a police officer walks in front of their house, he listens to a beautiful song. After some events, the officer enters the house and a lady wearing black is found dead in the white room. There are a lot of characters, about 15 suspects, and the plot twists many times "Eleven o'clock and a windy night!" might have been the cry of medieval watchmen at that hour on the 24th of July. Constable Mulligan was more reticent, as it formed no part of his duties to intimate publicly the time or the state of the weather. Nevertheless, the bells of the Anglican Church, Troy, London, S.W., chimed the hour through the clamor of a high wind; and those people who were not in bed must have decided to retire. Not that anyone appeared to be stirring. The lights were extinguished in all windows within the range of Mulligan's vision, and the flashing of his lantern on the doors and gates in Achilles Avenue showed that they were discreetly closed. Not even a tramp or a cat enlivened the roadway. Mulligan was apparently the sole waking person in a sleeping world. Few readers will anticipate the ending of the story.