Henry Cavill has just signed on to play legendary sleuth Sherlock Holmes for Legendary Pictures' upcoming adaptation of the Enola Holmes Mysteries. Cavill will star opposite Millie Bobby Brown, who will play Sherlock's teen-aged sister, Enola. Helena Bonham Carter is already on hand to play Enola's mother.

The Enola Holmes movie will be directed by Harry Bradbeer, with a script written by Jack Thorne. Brown will be producing with Paige Brown under their PCMA productions label, with Legendary pictures picking up the tab for the rest of the production.

The Enola Holmes Mysteries were started in 2006 by American author Nancy Springer, and led to six books in total. The stories of Enola and her older brothers, Mycroft and Sherlock, actually fit fairly well into the Holmes canon established by Arthur Conan Doyle.

In the series, Enola wakes up to find her mother missing, and is suddenly the ward of her stodgy brother, Mycroft, who expects her to become a proper lady:

When Enola Holmes, sister to the detective Sherlock Holmes, discovers her mother has disappeared, she quickly embarks on a journey to London in search of her. But nothing can prepare her for what awaits. Because when she arrives, she finds herself involved in the kidnapping of a young marquess, fleeing murderous villains, and trying to elude her shrewd older brothers—all while attempting to piece together clues to her mother's strange disappearance. Amid all the mayhem, will Enola be able to decode the necessary clues and find her mother?

The Enola Holmes Mysteries sound like a fantastic and entertaining project for Brown. There were a total of six Enola books published, so it's not like Legendary is going to run out of source material any time soon. Millie Bobbie Brown will next be seen on the third season of Stranger Things on Netflix.

Cavill has been working on the television adaptation of the highly popular book and game series, The Witcher, which will also appear on Netflix.