Season: Four — Episode: 7 Director: Guy Ferland — Writer: Tamara Jaron — Aired: January 7, 2016 — Viewers (millions): 6.71 Summary: The duo goes against a clever opponent, who forces Holmes to think out of the box. Meanwhile Watson's troubles with her father are brought into focus when he writes a book about her and Holmes.
Sherlock and I do not run around with guns and we don't get into kung fu fights with criminals and we sure as hell do not sleep together.
— Joan to Henry
At the 11th Precinct, Captain Gregson calls Joan into his office and shows her a fictional book that is written about her and Holmes, with many artistic liberties. At a construction site, workers find a body has been put through a wood chipper and an FBI badge. At the Morgue, the remains are identified as retired FBI Agent Robert Underhill. Incapacitated by pepper spray, Holmes speculates the Agent was lured to the site by his killer. Underhill's wife Sheila is questioned at the precinct but has an alibi. She indicates they were separated and though retired, he was looking into old cases and told her he was close to cracking one. Having discovered her step-father is the author of the book, Joan confronts Henry at his house. She's bought all hard copies she could find and he doesn't understand why she's so angry. After she demands that no more copies be published, she tells him Holmes doesn't know about the book.
That is how you make a porn name, not a pen name!
At The Brownstone, Joan finds Holmes has lined rooms with three case files Bob Underwood had in his home. Holmes has solved all three and believes none resulted in Underwood's death. However, he found that Underwood requested the case file of Nina Davenport. Nina was kidnapped at age 4, escaped and returned ten years later. Her kidnapper was never found and Holmes finds it suspicious that her file was missing from Underwood's home.