Jane turning Harvey down. After years of putting up with his abuse cheerfully and devotionally, she finally calls him out and rejects his offer of marriage. It's so shocking to Harvey that he actually starts to respect her and realizes how important she is to him.
Diana volunteers at a seniors advocacy group after Tom accuses her (not entirely wrongly) of only complaining about unfair situations while he fixes them. While doing so, she saves an old woman from being swindled by a younger woman renting a basement apartment from her. It then emerges that the con artist is also Harvey's current girlfriend Janet, who is advising him to cram more residents into the retirement home through smaller apartments and shared bathrooms. Cue Harvey and Janet being arrested in full view of a local news program, thanks to Tom and Diana's quick thinking.
Early in the series, Diana steals her niece's Porsche and takes Tom to the seaside for the day. On the trip home, they are stopped by the police (contacted by Harvey), who are under the impression Diana is unfit to drive. Upon their return, Tom swiftly demonstrates that Diana was fully capable of driving (having a valid licence), implies that their traffic stop was ageist, and gets Harvey arrested for wasting police time.
Harvey, Geoffrey, and Marion hire a psychiatrist to judge whether Tom and Diana are capable of managing their affairs, with the goal of having power of attorney taken away from them. Tom and Diana learn of the plan and pretend to be completely insane, convincing the psychiatrist that they know fully well how to look after themselves. (Of course, it helps that the psychiatrist is a friend of Diana's niece, who isn't nearly the terrible person she's initially made out to be by her aunt.)