Forensic psychiatrist Natalie King returns in a new locked-room mystery by a beloved Australian author Natalie King may be a psychiatrist, but that doesn't mean she can persuade her baby to go to sleep. Sienna wants to party through the night-and lack of sleep is a major trigger for Natalie's bipolar disorder. Sleep school at Southside private psych unit, however, turns out to have its own hazards. It's bad enough that Natalie doesn't really want to be there, that she wants to keep her professional status quiet and that she's seen enough group therapy to be quite sure it's not her thing. But then someone arrives who Natalie knows very well indeed-and not in a good way. Luckily she's out of Southside by the time the murder happens. Unluckily, she knows everyone who's involved, including the cops. They think they have an open-and-shut case. Natalie's pretty sure they've locked the door on the wrong person.