Retired academic philosopher Meg Thorne is annoyed that old people - especially older women - too often become invisible; as if they're a piece of furniture rather than part of the community. This, however, prompts her to imagine that a gang of elderly women would make perfect spies and detectives; like harmless Miss Marple, always underestimated in the corner of the sitting room. Meg's crazy notion becomes reality when she joins forces with two like-minded women: Dorothy, ex-publican now caterer and handywoman; and Lila, former social worker and one-time detective agency employee. The 'Grey Ghosts' are hired by a worried man to find out why his 85-year-old mother Sara, a resident of the luxury Sunnyvale Residential and Care Home, is living in fear. To investigate whether it's her 'old age' or something awry in the running of the home, Meg goes undercover as a temporary resident and Dorothy gets a job in the kitchen. What they assumed will be an easy task soon becomes difficult and dangerous. Sara is unable to explain what is troubling her, but Meg realises it's connected to a secret her friend Jenny told her - before being locked away in the dementia ward upstairs. And then the coronavirus pandemic complicates everything. Melbourne goes into COVID-19 lockdown and Meg is trapped inside Sunnyvale with all the other residents, isolated from her friends. When her escape attempt is thwarted, she finds herself in the upstairs ward, a supposed victim of Covid-19 placed in isolation. She learns the secret of Sara's fear but realises the truth will likely die with her, as the pandemic will give those responsible the perfect cover for her murder.