Redemption
Harriet is not really at all excited to go back to Shrewsbury College, not least because last time she was there, she was the defendant in a murder case. She is not sure how she will be received or how welcome she will be. When she returns she is pleasantly surprised. She receives a very warm welcome. Moreover, the Dean of the college actually wants her help, giving her the opportunity to be seen as the "hero" rather than as the "villain".
This offers a kind of redemption for Harriet that she did not realize she was looking for until she becomes immersed in the case. It is a case that offers considerable opportunity for introspection. She realizes that her dread of returning to Oxford has nothing to do with returning to academia - which she loves, and actually takes refuge in - or even returning to the student environment, which she remembers with love and fondness. It is caused by her prior experiences and feeling that she left under a cloud. The case offers her the opportunity to solve a mystery and get to the bottom of some vicious poison pen letter writing, giving her the redemption she is looking for, and making it possible for her to spend more time at her alma mater without fear or dread.
Feminism
On the face of it, this does not really appear to be a novel about feminism, although it is a novel with a strong and confident female protagonist. Harriet is a confident woman although she does suffer from self-doubt, not brought on by her own feelings about her life or her choices, but by her knowledge that she is not meeting society's expectations of her as a woman. She even makes reference to the fact that propriety dictates that she clean floors or engage in domestic duty rather than write mystery novels; her answer to that is that she should do what she is best at, being a rather bad housekeeper but a rather good mystery writer.
Another reference to the stereotypical view of a woman's role in society is made by Annie Wilson, who is a housekeeper at Shrewsbury College, and resents the female students all around her, because they are pursuing academia. She feels that this is not proper at all and that a woman should only pursue a life of domesticity.
Revenge
Annie wants revenge, and this is the motivation behind the bulk of her criminal actions. Her husband was guilty of academic fraud, which was discovered and brought to the attention of authorities by a college examiner who has subsequently moved to Shrewsbury College. She follows him there to get her revenge because she blames him for he husband's death.
Everything that Annie does is to get revenge, from vandalizing his slide collection to sending terrible poison pen letters. She also wants to get revenge on women who go against her ideas of what a woman should be doing. She is a woman who makes her choices from a place of hate and her need for revenge is the driving force behind this.
Love
Harriet has historically ambivalent feelings towards Lord Peter Wimsey. When they first met she was not even sure that she liked him very much. He fell immediately in love with her and proposed marriage, but far too quickly, which scared Harriet and made her totally rethink having any connection with him at all.
However, she was never able ton quite let go, maintaining a friendship with him and a dependency on him when putting his talents as an amateur detective to good use. The introspection offered by this case gives her the chance to untangle her feelings for Wimsey, and her conflicting feelings about love in general. It is a concept that confuses her and also a union that does not seem to make sense because they are both very opinionated, intelligent and sharp witted. She is not sure that this is a good combination. Ultimately, though, emotion wins out over common sense, and she eventually accepts his proposal.
