* Her Knowledge: Mrs. Stapleton is fully aware of her husband's plan to murder Sir Charles Baskerville. She helps him prepare the moor, assists in setting up the hound, and even participates in the deception.
* Her Deceptive Nature: She actively misleads Sherlock Holmes and Dr. Watson, playing the role of a helpless widow to further their husband's plan.
* Her Involvement in the Plan: She is not just a bystander; she is a vital part of the scheme. She assists in acquiring the ingredients for the hound's "phosphorous glow" and helps to create a believable alibi for her husband.
* Her Knowledge of the Hound: While she initially claims to be unaware of the hound, it is revealed that she knows exactly what it is and how it works.
* Her Willing Participation: She does not attempt to stop her husband's crime. Instead, she actively helps him to carry it out.
Therefore, Mrs. Stapleton is not innocent. She is a cunning accomplice who actively assists her husband in his murderous plot. Her role is integral to the success of the plan, and she is ultimately responsible for the death of Sir Charles Baskerville.