While visiting the land of Miss Marple and Sherlock Holmes, bookstore owner and amateur sleuth Samantha Washington finds herself on a tragical mystery tour. Sam joins Nana Jo and her Shady Acres Retirement Village friends Irma, Dorothy, and Ruby Mae on a weeklong trip to London, England, to experience the Peabody Mystery Lovers Tour. The chance to see the sights and walk the streets that inspired Agatha Christie and Arthur Conan Doyle is a dream come true for Sam and a perfect way to celebrate her new publishing contract as a mystery author. But between visits to Jack the Ripper's Whitechapel district and 221B Baker Street, Major Horace Peabody is found dead, supposedly of natural causes. Despite his employer's unfortunate demise, the tour guide insists on keeping calm and carrying on'until another tourist on their trip also dies under mysterious circumstances. Now it's up to Sam and the Shady Acres ladies to mix and mingle among their fellow mystery lovers, find a motive, and turn up a murderer.