Set in London, a serial killer targets trolls on the internet and then develops an ever-growing Twitter following because of the publicity surrounding the murders. The first to figure out what's going on is Freddie Venten, a part-time journalist and full-time barista, who happens into the investigation of the first murder through a chance encounter with a childhood friend, Nasreen Cudmore, now a police sergeant. Freddie nearly compromises the case and Nasreen's career by interfering. Making matters worse, the two had a falling-out as teenagers over a mysterious incident, which adds a layer of tension in the incident room when Freddie joins the team as the social media adviser. She's needed because the police turn out to be hapless at social media and in making connections between what happens there and the murders--a bit too hapless to be plausible. -- from Publisher's Weekly