The gripping new YA thriller from the author of FOUR GOOD LIARS, and the perfect read for fans of A GOOD GIRL'S GUIDE TO MURDER. How do you catch a murderer without knowing who the victim is? Science-obsessed Grace's fresh start with her dad in Devon is derailed when the smart speaker in their new house comes alive at midnight and says: I'm going to murder you. And after Grace begins to investigate, she uncovers four mysterious deaths - all supposedly accidents - that are linked to the device. But only Grace knows that one of those deaths was actually a murder - and now she must identify both the victim and the killer, using the methodology of a chemistry experiment ... before she ends up dead herself. The gripping new YA thriller from the author of FOUR GOOD LIARS. "An immaculately plotted, clever book with a great ending!" Sue Wallman, author of Lying About Last Summer