Zeroth

It's almost a Holmes-Moriarty thing; each Holmes deals with their own Moriarty. Mycroft has Albert, Sherlock has William, as for Enola...

Surprise, surprise! The Moriartys also got a ball of mischief and intelligence in Eleanor Moriarty, their personal dark horse and a hidden card many often overlook. Enola's personal counterpart, the black to her white.

Eleanor makes the puzzle, and Enola tries to decipher it. Put your bet; who'll outwit who?