The Case of the Disappearing Duchess: Enola Holmes 6

As Enola searches for the missing Lady Blanchefleur del Campo, she discovers that her brother Sherlock is just as diligently searching for Enola herself. He needs her help to decipher a message from their long-lost mother. Sherlock, Enola, and their brother, Mycroft, must solve a triple mystery: What has happened to their mother? And to Lady Blanchefleur? And what does either have to do with Mycroft, who holds Enola's future in his hands?