Iris Hollow and her two older sisters are unquestionably strange. Ever since they disappeared on a suburban street in Scotland as children only to return a month a later with no memory of what happened to them, odd, eerie occurrences seem to follow in their wake. And they're changing. First, their dark hair turned white. Then, their blue eyes slowly turned black. People find them disturbingly intoxicating, unbearably beautiful and inexplicably dangerous.

But now, ten years later, seventeen-year-old Iris Hollow is doing all she can to fit in and graduate high school on time - something her two famously glamorous globe-trotting older sisters, Grey and Vivi, never managed to do. But when Grey goes missing without a trace, leaving behind bizarre clues as to what might have happened, Iris and Vivi are left to trace her last few days.They aren't the only ones looking for her though. As they brush against the supernatural they realise that the story they've been told about their past is unravelling and the world that returned them seemingly unharmed ten years ago, might just be calling them home.