The day Louisiana teenager Rory Deveaux arrives at her new London boarding school, a series of brutal murders breaks out across the city, gruesome crimes mimicking the horrific Jack the Ripper events of more than a century ago. The police are baffled. But Rory discovers she can see the murderer when no one else can --- and he’s not the only one she sees.

Ginny Blackstone spent last summer traveling around Europe, following the tasks her aunt Peg laid out in a series of letters before she died. When her backpack is stolen --- with the last little blue envelope inside --- she resigns herself to never knowing how it was supposed to end. That is, until a mysterious boy contacts her months later.