Pomeroy's Postscript by Mary Fitt

When Pomeroy Parker went to stay in the country with old Mrs. Livingstone, his sister Marguerite expected a long letter from him telling her all about the house, the countryside, and Mrs. Livingstone herself (since neither Pomeroy nor Marguerite has ever set eyes on her before). Pomeroy, unlike most brothers, was a very good letter-writer and loved describing things, even if his handwriting was pretty bad.

But the weeks went by and all that Marguerite heard from Pomeroy was in a postscript to a letter written by someone else: a typewritten letter from Cousin Job. Cousin Job was a lawyer, his letter a warm invitation to Marguerite to join her brother as Mrs. Livingstone's guest. Pomeroy's postscript said simply: "Dear Sis, do come."

Why did Marguerite hesitate for a moment before accepting? And why did she find when she arrived?

REVIEW:
I originally read Pomeroy's Postscript as a kid in my local library and the story stuck with me (though the title did not).  Decades later I was able to track down the title and ultimately a copy of the book, but I shelved it without rereading.  I recently rediscovered the book on my shelves and am delighted to report it was as enjoyable a read now as all those many years ago.  I like that it is an adventure story that focuses on a female character (Marguerite) rather than on her twin brother (Pomeroy).  Sort-of cousin Merritt is another great character that rounds out the story - bookish and clever but somewhat uncertain of himself socially.  Though the book was written in the 1950s, there isn't actually much about it that is dated (other than a few lines at the very end about Uncle Sam handling everything as if Aunt Maud wasn't capable of doing so).  All in all an enjoyable reread of a story I very much enjoyed as a kid.