The True Queen

In the follow-up to the "delightful" regency fantasy novel (NPR.org) Sorcerer to the Crown, a young woman with no memories of her past finds herself embroiled in dangerous politics in England and the land of the fae.
When sisters Muna and Sakti wake up on the peaceful beach of the island of Janda Baik, they can't remember anything, except that they are bound as only sisters can be. They have been cursed by an unknown enchanter, and slowly Sakti starts to fade away. The only hope of saving her is to go to distant Britain, where the Sorceress Royal has established an academy to train women in magic.
If Muna is to save her sister, she must learn to navigate high society, and trick the English magicians into believing she is a magical prodigy. As she's drawn into their intrigues, she must uncover the secrets of her past, and journey into a world with more magic than she had ever dreamed.