The biggest setback in the new Netflix mystery casts all the Sherlock Holmes and Enola Holmes books in a new light.
The big revelation in Enola Holmes 2 isn't just about a post-credits scene that links old school Holmes canon to Nancy Springer's books.
Yep, there's a surprise cameo at the end, which will please all sorts of Sherlockian fans.
Before that happens, in the larger segment of the film, we get another very famous Sherlock Holmes character.
For the second Enola Holmes film, both Sherlock and Enola (Henry Cavill and Millie Bobby Brown) grapple with a corruption mystery.
Brilliantly played by Sharon Duncan-Brewster, Miss Mira Troy, Lord McIntyre's (Tim McMullen) assistant actually goes by another name.
Sarah Chapman's disguise as "Sisley" is a reference to the second Nancy Springer book, The Case of the Left-Handed Lady.
In which Enola attempts to solve the disappearance of a character named "Lady Cecily Alistair".
Although Enola Holmes 2 is quite different from the other Enola Holmes book, this Easter egg combines the two in an interesting way.
Inevitably, even in his first appearance, Moriarty was retrospectively revealed to have been in the shadows all along.