Megan Melvick has returned home after a three-year absence to visit her dying sister, Melissa, for the last time. As she approaches the grand Scottish country estate where she grew up, the memories come flooding back. Just what did happen on the night of Melissa's wedding five years before? Where has Megan and Melissa's mother disappeared to? And why does Melissa whisper that solitary word before she finally slips away: Sorry.

In order to overcome her demons, Megan must confront her painful recollections of that terrible night, the night of Melissa's wedding. The night somebody died. But can she really trust her memories? And who is so determined that she should forget?