I bought this book on the strength of its cover, not having read the reviews here - my mistake.
It purports to be a 'horror/ghost' story, but its major failing is that it is not at all scary - in fact for the first half of the book I thought maybe it wasn't a ghost story at all but some sort of mid-life crisis story about the central character - Conrad. (I should point out that I am very easily scared with an over-active imagination and have to sleep with the lights on after watching scary films so if you can't scare me, you're not going to scare anyone!)
As several other reviewers have pointed out - the ending is just terrible - really rushed and badly executed. The device by which Conrad finds out what happened to Alma is levered in with a crow-bar and even then large parts of it are nonsensical. Either leave the past as a mystery or explain it properly!
The idea behind the book is sound but just wasted in poor execution. The initial characterisation is ok too - but Conrad's & Jo's descent into 'madness' is too abrupt and not at all convincing. Take The Shining as a benchmark and this falls far short.
All in all I found this to be a very unsatisfying read and would not recommend it.