Sorcerer of the Crown / Zen Cho.

English magic faces its darkest hour. In Regency London, Zacharias Wythe is England's first African Sorcerer Royal. But how can he enjoy his position, while a faction schemes to remove him? He's also haunted by his dead mentor, and the Fairy Court is refusing to supply England with magic ... just when the government demands it for their blasted French war. Ambitious orphan Prunella is determined to escape a life of drudgery. So when the beleaguered Sorcerer Royal visits the school where she works, she seizes her opportunity. Prunella's stumbled upon the greatest magical discovery in centuries - and intends to use it. The last thing Zacharias needs is a female magical prodigy! But together, they could change sorcery forever. - Publishers description.