At the illustrious Greyscott Academy, reputation is everything. For Meg, the daughter of the school's janitor, the rules are simple: keep your head down, don't step on any rich kids' toes and stay invisible until graduation. That is, until the glamorous Wren twins - the beautiful, troubled Lottie and the magnetic Sebastien - decide to take Meg under their gilded wings. But not all that glitters is gold. After a disastrous incident at Greyscott's famous Midsummer Ball, Meg finds herself on the outs.

Desperate to make amends, Meg gratefully accepts an invite to the twins' Halloween party at Wren Hall, a windswept manor complete with a ruined, towering folly. But nothing goes to plan. And when one of the party-goers disappears and a violent storm traps the group inside the house, she realizes there's more to the Wren twins than meets the eye . . .