She Left: A Novel - Stacie Grey

Twenty years ago, she survived. This time she may not be so lucky.
On the night that changed everything, Amy Brewer walked out of a house party, trudging angrily away from the friends who made her feel like she didn't belong. Within the next hour, all five of those friends would be dead.
The Memorial Day Massacre, as it came to be called, rocked their small California community and Amy-the girl who had walked away just in time-couldn't escape the media circus...or the guilt.
Twenty years later, ten people with connections to the crime have been invited to a remote cliffside house by a journalist looking to do a story on the murders. But the group quickly learns the event is not what it seems. As a storm closes in and guests begin to die, Amy realizes there is someone in the house who knows more than they admit about what happened that night long ago. and they will stop at nothing to protect their secrets.