The Osborne Case

"Janet Markham has been trying to track down Gretchen Falkirk for months. She’s eager to learn more about Alberta Montgomery, one of the previous residents of the bed and breakfast she now owns with her sister, Joan.
When her friends from the Isle of Man, Bessie Cubbon and Doona Moore, come for a short stay, it seems the perfect time to try visiting the elusive woman. Unfortunately for Janet, instead of finding Gretchen, she finds herself and her friends caught up in the hunt for a missing person.
She and Joan want to show Bessie and Doona the sights around Derbyshire, but Janet wants to find Gretchen at least as much."