This is a very mediocre book by a writer whose gifts and substantial early promise appear to be deserting him. The characters are preposterous and John Henderson is clearly a piece of authorial wish fulfillment: a non-sexist, honest, decent action hero with a vast source of hidden income who the (good)ladies adore because he is so open about his feelings. Pass the sick bag. I finished it and, to be fair, Marshall shows enough skill here to keep this creaking plot afloat until the bitter end: hence the two stars.
Maybe Marshall is trying to expand his horizons a bit by branching out into more supernatural fiction but on the evidence of this and The Intruders, he should stick to what he is good at.
Finally, what is the cover all about? It has nothing whatsoever to do with this story and I can only assume that it is a shameful attempt to trade on past glories. I know I was fooled.