​Precocious Charlemagne Crosse had an idyllic childhood until the night her parents Sir Archibald and Lady Lavinia vanished in the aftermath of a solar eclipse. Shipped off to disreputable boarding schools, Charlemagne's life is bleak. However, on her sixteenth birthday, Charlemagne unexpectedly regains her wealth and freedom. Upon her return to the ancestral Crosse mansion, she's reunited with black sheep Uncle Alistair and his new family: his wife, the exotic Antoinette, and her peculiar daughter Simone.
Charlemagne is summoned to a meeting with the mercurial Queen Victoria who still grieves for her late husband Prince Albert. Victoria reveals that Sir Archibald, an eccentric inventor, was under Crown orders to devise a way to contact Albert in the afterlife. The queen is convinced that only Charlemagne can decipher the clues that her father surely left behind.
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Supported by a cast of diverse characters, Charlemagne embarks on a perilous journey through the seedy underbelly of an alternate Victorian London. And with another solar eclipse looming, it might be Charlemagne's best—and last—chance to reunite with her parents.