In "A Scandal in Bohemia," the mood is mysterious and exciting without ever reaching any particularly intense height. Only at the end is the mood marked by shock for the reader.
The story's genre of detective fiction gives the reader an expectation of suspense right away. However, Doyle deviates from some of the genre's conventions and thereby sets "A Scandal in Bohemia" apart from typical detective stories. For example, Holmes's project does not revolve around solving a crime or unveiling a mystery. Instead, he has been hired to retrieve a photograph. The frequent use of disguise in the story, as well as the uncertainty surrounding Irene Adler's aims, certainly imbue the story with some mystery for the reader, but the mood is not as suspenseful as stories in which a crime has taken place or something totally inexplicable is going on.
When Watson passes Holmes's lodgings in Baker Street in the exposition, the mood is shaped by the image of Holmes pacing around his room. The mystery and excitement that this image conjures up are reinforced by the anonymous letter, and the two men's initial deductions around it. The King of Bohemia's visit dispels some of this mystery, as his ridiculous appearance gives the mood an air of comedy. Holmes's unwillingness to take the character seriously also prevents the mood from reaching any suspenseful heights. As both Watson and the reader take their cues from Holmes, it is when he is at his most excited or perplexed that the mood is the most intense. Additionally, scenes marked by dramatic irony—especially if the protagonist is the one in possession of a secret—often feature an intensification of the mood, as the reader wonders or worries whether a character will be found out. The main instance of dramatic irony in this story takes place in the second part, when the disguised Holmes feigns injury to enter Briony Lodge and Watson throws a rocket through the window. Although neither they nor the reader realize it at the time, this is when Irene Adler begins to catch onto what is going on.
The mood diverges from its steady and mildly mysterious status at the very end, when the plot twist brings the reader surprise. It is perhaps precisely because the mood never reaches any great suspense over the course of the story that it is able to end on such a remarkable plot twist. Holmes is overly sure of himself until the end, which prevents him from ever getting terribly worked up. Rarely stopping to doubt himself, he believes he has everything under control. It is only in the final pages, when Irene Adler's triumph over Holmes has been revealed, that the full extent of the story's mystery comes to light.
