Has been read and has a cracked spine and some bends in the cover. YA high-school/boarding school thriller
 
"In the last day of summer, Grace Fairchild, the beautiful young wife of real estate mogul Allister Calloway, vanished from the family’s lake house without a trace, leaving behind her seven-year old daughter, Charlie, and a slew of unanswered questions.

Years later, seventeen-year-old Charlie still struggles with the dark legacy of her family name and the mystery surrounding her mother. Determined to finally let go of the past, she throws herself into life at Knollwood, the prestigious New England school she attends. Charlie quickly becomes friends with Knollwood’s “it” crowd.

Charlie has also been tapped by the A’s—the school’s elite secret society well known for terrorising the faculty, administration, and their enemies. To become a member of the A’s, Charlie must play The Game, a semester-long, diabolical high-stakes scavenger hunt that will jeopardise her friendships, her reputation, even her place at Knollwood.

As the dark events of past and present converge, Charlie begins to fear that she may not survive the terrible truth about her family, her school, and her own life."