There have always been apparitions on the tube, faces on the other side of the window alongside yours, momentary glimpses into another world were enough to make the hairs on the back of your neck stand up. Just recently, however, there has been a proliferation of sightings on the Metropolitan Line and these spirits are really starting to scare people. The only people in the Metropolitan Police that can deal with this are the Special Assessment Unit a.k.a. The Folly, so Peter Grant is despatched along with Jaget Kumar from the British Transport Police to suffer the perils of the rush hour and to find out what has spooked the ghosts.
Abigail, Peter’s cousin has started turning up to the Folly and as she is showing potential for magical things, Nightingale takes it upon himself to train her as well. There is the possibility that a new River God has turned up, but as he is very young, Peter needs Beverly to come and see him, they form an instant bond and surprise the older couple looking after him as they vanish in the river. As they close in on the reason that the ghosts are agitated, the search takes on a new urgency when they realise that someone may be in danger and they are fast running out of time.
This is a really good novella that slots into the fantastic Rivers of London Series. Written with the same humour and wit as the previous ones it fills in more detail to the characters of Grant and Nightingale as well as introducing Abigale for the first time. It was nice to see Nightingales’ play a larger part in this as he has always been in the shadow of Grant to a certain extent. If it had one flaw, it is way too short; but it was great to see that there is book seven coming next year. 4.5 stars