CBS

Season 2: Episode 12 - The Diabolical Kind

The Diabolical Kind: After a young girl is kidnapped, Sherlock and Joan recognize the voice of the kidnapper as "faux-riarty,” one of Moriarty’s lieutenants. Sherlock reveals he’s been writing to Moriarty and, as part of her deal with the feds, she is brought in to consult on the case. Two policemen are killed as Simon (aka "faux-riarty”) obtains the sketches of the suspects that Moriarty drew, and Sherlock notices a code in the drawing and immediately suspects Moriarty’s involvement. In cracking the codes, Sherlock learns the kidnapped girl is Moriarty’s daughter. Moriarty escapes custody, finds and kills Simon to rescue the girl, but almost dies in the process.