In modern-day London, sixteen-year-old Miss James "Mori" Moriarty is looking for an escape from her recent past and spiraling home life when she takes classmate Sherlock Holmes up on his challenge to solve a murder mystery.

In modern-day London, sixteen-year-old Miss James "Mori" Moriarty and classmate Sherlock Holmes set out to discover who is framing Mori for the Regent's Park killings.

Mori escapes captivity in the English countryside and returns to London, where she plots the downfall of her father and his cohorts but discovers that Lock may no longer be an ally.