A renowned professor is found dead. She came to fame in the 1990s by publishing a book on why women don't need men but now her dating site video has somehow found its way onto a gossip site. Most indications, including Dr Hobson's analysis, point to suicide but Lewis is not convinced.
The best Lewis episodes have interesting sub-plots involving characters and their relationships, making for an engaging story. This has such a sub-plot and its ultimately quite engaging, emotional and thought-provoking. There's also a sub-plot involving a new DI who seems to hit it off with Dr Hobson, causing Lewis some degree of angst and jealousy and providing some levity to proceedings.
As far as the main plot - the death - goes it is one of the better ones in the Lewis series. Initially it's not even necessarily a murder. Furthermore, it's not one where the motive and perpetrator are left-field and are revealed in an out-of-the blue development in the last 10 minutes. The plot develops at a nice pace and the ultimate backstory isn't unnecessarily complex or contrived.
The episode also covers some interesting themes, all of which are even more relevant today than they were in 2012: privacy, especially online privacy, online trolling and generally the problem of balancing freedom of speech and expression and freedom from harassment that the internet presents.
Excellent episode.