Fiona, Sue, and Daisy — three charming old ladies who work as volunteers in a charity shop during the day and solve crimes at night. Summer has come to the coastal town of Southbourne, and that means the elderly ladies are ready for a new season of sun, sea, and... murders.
In summer, the whole of Southbourne heads to the Madford-Spit coastline with its stunning landscapes and colorful beach bungalows. One such bungalow, adorned with whimsical shells, always stood out among the others. Until one night, it burned down under the most mysterious circumstances. Along with it, an unsuspecting old man, Malcolm Craney, who was sleeping inside.
The local residents' association hires our charming detectives to investigate the case. They quickly manage to compile a long list of suspects — the eccentric old man has upset many. Surprisingly, the nighttime arsonist managed to avoid all security cameras and was not captured on any video footage. But the most important thing is the method of the arson. The method is absolutely inconceivable and defies any logical explanation…