In a Dark, Dark Wood, Ruth Ware

Someone's getting married. Someone's getting murdered. 
The next big thing in crime fiction -- we've had toxic marriages, this is about toxic friendships.

     In a dark, dark wood 

     Nora hasn't seen Clare for ten years. Not since Nora walked out of school one day and never went back. 

     There was a dark, dark house

     Until, out of the blue, an invitation to Clare's hen do arrives. Is this a chance for Nora to finally put her past behind her?

     And in the dark, dark house there was a dark, dark room

     But something goes wrong. Very wrong.

     And in the dark, dark room.... 

     Some things can't stay secret for ever.