Last October, Alice Ogilvie's ex-best friend, Brooke Donovan, was killed—and if it weren't for Alice's unlikely alliance with her tutor, Iris Adams, and her library of the complete works of Agatha Christie, the wrong person would almost certainly be sitting in prison for the crime. The Castle Cove police aren't exactly great at solving crimes. In fact, they're notorious for solving crimes. Which is why, on the night of Castle Cove High's annual Sadie Hawkins dance, Alice takes the opportunity to explore Levy Castle—the site of one of Castle Cove's most infamous deaths. Mona Moody—the classic film star—died there almost a century ago, and Alice is pretty sure the police got that invest­igation wrong, too. But before she can even think about digging deeper, she walks right into the scene of a crime. Rebecca Kennedy, on the ground in a pool of blood. And standing over Kennedy? Another one of Alice's ex-friends—Helen Park. The Castle Cove Police Department thinks it's an open-and-shut case, but Alice and Iris are sure it can't be that simple. Park isn't a murderer—and the girls know all too well that in life, and in mysteries, things are rarely what they appear to be. To understand the present, sometimes you need to look to the past. Castle Cove is full of secrets, and Alice and Iris are about to uncover one of its biggest—and most dangerous—secrets of all.