When Edith Averly is sent to investigate a murder at Green Briar Lunatic Asylum, a rambling gothic institution on the edge of the Cornish moors, she’s horrified to realise that in order to infiltrate the asylum, she’ll have to pretend to be mad herself…

Several weeks before her arrival, her beloved father stipulates in his will that his reclusive but strangely-gifted daughters must live apart from each other for a whole year in order to retain their family home. As a further condition of their inheritance, he assigns them each a crime that he was unable to solve during his recent years of armchair detecting.

The eldest sister, Edith, can see echoes of violent events from the past. So when she is sent to the remote Cornish asylum where the brutal murder of Dr Hawkins took place seven years ago – she is quickly overwhelmed by her disturbing visions and begins to fear for her both her sanity and her safety...

Because Green Briar is a place that asks more questions than it answers. Such as, why is the darkly-handsome new doctor in charge unable to meet her eye? Where do the patients keep disappearing to? And who are the Lantern Keepers and what are the secrets they keep?

Only Edith can find out… if Dr Hawkins’ killer doesn’t find her first.