One interesting narrative strategy is to violate your own premise. For instance, Spock on Star Trek was strongly established as showing no emotions whatsoever. Some of the most interesting episodes tho, put Spock in situations where he did show emotion, and the anomaly entertained us.
As a recent widow, Lady Julia Grey, has few prospects in life, her options closed off by the mores of her times. She has some remarkably modern sensibilities, tho, and when she comes to suspect her husband was murdered, she takes an active part in the investigation, which includes such unlikely events as visiting a gypsy camp at night, searching a servant’s pornography collection, and discussing syphilis with a prostitute. Not at all what a proper Victorian lady would do. And the anomaly entertains.
References to Northanger Abbey and Wuthering Heights are pretty explicit here. Her Heathcliffe character is Nicholas Brisbane, private detective and smoldering hunk. If the mystery isn’t quite as mysterious as it ought to be (not enough suspects) the novel still has much to recommend it. The first paragraph, for instance. "To say that I met Nicholas Brisbane over my husband’s dead body is not entirely accurate. Edward, it should be noted, was still twitching on the floor."
Or the ending: "I did not know when I would see Brisbane again, but I knew that I would. Someday. And indeed I did. That is when we found the body in the chapel. But that is a tale for another time." Reader, there’s to be a sequel.