This episode inspires these questions of Fridge Logic:
It's never explained why Wallace's bags were packed, with stolen silver, and cash.
Actually it is. Sid says Wallace regularly steals the silver to gamble with and the wins it back.
Somehow, despite Father Brown being familiar with her award-winning journalism work, nobody seems to recall Rosie Everton losing her big-paper London career over a (wrongfully) disgraced article about aircraft safety. It's a mystery to everyone why she's in Kembleford.
Nobody challenges Dr. Jackson suddenly leaving to return to London after stating that he was planning to write his next book in Kembleford, and he has barely started.
When Twyman is found with Everton's dead body, he's suddenly the new suspect for not just her murder, but also his son's, with Wallace immediately let off the hook. Nobody explains and few even try to theorize why he would kill both of them. (Father Brown suggests it was because Calvin found out about the Twyman Aircraft safety cover-up, which is still an awfully unlikely motive, but that is shot down.)
Wallace briefly lets Everton in to copy the secret musical piece that Calvin received, out of a spirit of fair play. The sheet music is four pages and extremely dense with complex quarter and eighth note sections. It's never explained how she is able to copy it all down in a short window of time; it would seem to take easily a half hour.
