Book 136: The Furthest Station

The Furthest Station by Aaronovitch is a novella in the Peter Grant series that takes place between books five and six.  Peter is called to investigate a sudden increase in ghosts on the Metropolitan Line that behave in a strange manner and then disintegrate.  After speaking with one of the ghosts, Peter realizes that a real person has been kidnapped, and the ghosts are trying to find someone to help her.  With Nightengale for the heavy lifting and his cousin Abigail to help with the grunt work, the Folly assists the regular police with their investigation.  4 stars.