The Mystery of Jayden Holmes (A Greg Lestrad...
Jayden Holmes. The third Holmes no one knew about. Why? Because she left Sherlock, her twin, for a life of crime with Jim Moriarty. Years after her disappearance, she is back in England and only truly ready to turn over a new leaf when Moriarty betrays her and D.I. Greg Lestrade catches her eye.
Continued in book 2, The Hunt for Victoria Holmes.