Plot Summary:Sherlock Holmes is asked by Jack Bennett to investigate after his fiancée Edith Presbury sees the shadow of a man in her window in the middle of the night. The problem is that her bedroom is on the second floor and there is no way for any man to have been able to get to that window. Edith is the daughter of a notable natural scientist, Professor Presbury, a widower who is engaged to be married to a much younger woman, Alice Morphy. The Professor is quite displeased at hearing that Bennett, who also happens to be his assistant, has hired the Great Detective and Holmes and Watson are unceremoniously escorted off the property.When Holmes reads of a rash of thefts from zoos - all monkeys and apes - he slowly begins to unravel the mystery of the shadow Miss Presbury saw in her window.