The Crimson Queen (BBC Sherlock fanfiction)

Sherlock Holmes has a case. But this is not any ordinary case.

Evanna Holmes is the intellectual visitor and she informs him of a murder, the murder of her mother Alia Holmes- Sherlock's unknown older sister.

But once Sherlock and his trusty companion Dr John Watson agree to investigate it plummets them all into a dangerous world of secrets and mystery.