Bernie's Aunty Dot is worried that her favourite member of staff at the Care Home where she lives is being unfairly suspected of murdering another of the residents. She calls on their good friend DCI Jonah Porter to investigate. He discovers that Care Assistant, Jonathan Bates, is by no means the only person with a motive for killing Olive Carter – or, for that matter, the only person with means and opportunity to do so. It's a tough case, and Jonah decides that he needs to go undercover to solve it.