In The Wrong Category by Ruth Rendell, the main character, Barry, has been stalking the streets at night, visiting the spots where several murders have occurred. This seems to be either a very strange hobby or the suspicious actions of a murderer himself. One night, Barry meets a brunette woman in the bar who fits the description of the killer's preferred victims. Barry, however, is seemingly shocked at the woman's behavior. Not only is she not afraid of him, she is acting out of the ordinary for a woman of her time by hitting on him.

At first glance, she seems like she's trusting of him because he's an unassuming, innocent-looking man who seems like more of a nerd than a dangerous individual. Barry, on the other hand, seems surprised, and this could offer readers another reason to believe him to be guilty of the murders. For example, if Barry were indeed the murderer, he would likely have a negative opinion of women and believe them to be inferior to him. Therefore, he would feel uncomfortable if women were to step out of "their place" in society. He would view it as an affront that his next victim was so outgoing, and it would possibly make him nervous.

However, after reading the entire story, the reader can go back and change their perception of the exchange. We see now that Barry is simply nervous about the woman because she doesn't fit the profile of the victims—rather, she fits the profile of a possible killer. They go to the spot where the last murder occurred, and the woman runs. Why? Well, perhaps because Barry lets on that he knows about the murders and takes her there, essentially making her believe that he has caught her in the act: a lady murderer!

Indeed, gender expectations and role reversal play a large part in our own perception of the story upon first read. The plot twist works because it goes against all of our own previously held beliefs about gender roles and who is the most likely culprit as a serial killer whose primary targets are women.