The third Peter Grant urban fantasy detective novel by Ben Aaronovich. It’s quite good, but not quite up to the excellence of the first two (Rivers of London and Moon Over Soho). This time Peter is seconded to an almost normal murder enquiry, with just a hint of weirdness. The weirdness escalates slowly through the case, to the dismay of the murder investigation team. There’s a sub-plot following up on the ongoing story arc about illicit magicians and there’s nice character follow-on with Peter and new recruit to the team Lesley. Another of Peter’s many relatives is introduced as a probable ongoing character (a mouthy thirteen year old cousin). As the name suggests this novel dives into the London Tube system, lovingly used by many for supernatural fictive inspiration before by the likes of Neil Gaiman (Neverwhere, soon to be revamped as a radio play by BBC Radio 4/Extra). It’s a decent read but just felt slightly thin compared to the previous two. The plot plods along ((pun intended) as a more-or-less normal murder enquiry, just with added magic. It’s all a little bit mundane. Still a cut above many in this oeuvre, but I hope Aaronovich can raise his game back up to the first two in the future.