When someone commits robbery and murder aboard the luxurious train on which Myrtle Hardcastle, her Aunt Helena, her governess Miss Judson, and cat Peony are traveling, Myrtle is determined to find the culprit.
Washed ashore as a baby in tiny Tupelo Landing, North Carolina, Mo LoBeau, now eleven, and her best friend Dale turn detective when the amnesiac Colonel, owner of a café and co-parent of Mo with his cook, Miss Lana, seems implicated in a murder.
When twelve-year-old aspiring detective Myrtle Hardcastle learns her neighor in quiet Swinburne, England, a breeder of rare flowers, has died she is certain it was murder and that she must find the killer.