Stroud has come up with an interesting storyline - ghosts have become a major problem in England, but the only people who can see or hear them are children. So children with this gift (or curse) are trained to rid England of ghosts or become nightwatch-kids to protect entries to buildings - all very dangerous jobs.
It's quite horrifying that children are put in often fatal situations, protecting adults from the very things the adults should be protecting them from. This ghost-wormed England is quite topsy-turvy to our current day world and almost Victorian in its child-labour aspects. Stroud's characters face down situations that would make an adult run screaming - but these 'psychic investigator's' are resigned to their role in society. It's in their speech and actions, it distances them from ordinary people. They know the reality of what's out there and that it will probably kill them, whilst others get to live normal lives.
The whole concept was wonderful. I cannot wait for book two.
