Sleeping Murder Agatha Christie

Sleeping Murder by Agatha Christie
Newly weds Giles & Gwenda we looking to settle in the UK – moving from New Zealand.
Gwenda is driving the countryside looking for a house to buy when she sees Hillside and is entranced. However once the purchase has gone through she keeps hitting weird things like thinking there should have been a door in a particular place, that steps on the patio should be somewhere different and a particular pattern in a bedroom should be a particular wallpaper then finding that pattern in the back of a wardrobe.
Gwenda thinks she is going mad – however its pointed out to her when she meets Miss Marple  in London that she might actually be recovering childhood memories. Further digging shows she once did actually live in that house but that in turn triggers a memory of a murder she must have seen as a child. The young couple proceed to dig into her fathers death in a sanitorium, the sudden and permanent disappearance of her stepmother Helen. This brings in Dr James Kennedy Helen’s brother, Helen’s highshool boyfriend Jackie Afflick, Walter Fane one of Helen’s devoted admirers and last but not least Major Richard Erskine who was also in love with Helen. However who was the killer – Gwenda’s childhood remembrances are vague and when they try and follow leads they all form dead ends.
This story is a change from Agatha’s usual style in that the murder was committed over 20 years earlier and for a while they aren’t even sure there was a murder. The story revolves around digging into the past and history of all the suspects, following up old servants and checking up where every member of the cast was at the time.