Stewie and Brian star in a Sherlock Holmes parody.
After Stewie (Sherlock) and Brian (Watson) solve the case of the crown jewels and put Professor Moriarty in jail. As Watson gets ready for his upcoming wedding and Sherlock gets ready to retire, Scotland Yard sends him a letter, asking him for help. After reading it, Sherlock finds out that it concerns the murder of the prostitutes with the letter "V" in their names and thinks it could be the work of the "Scottish Brute".
Tropes for V is for Mystery:
- Black Comedy: Brian and Stewie playing Heart and Soul on Meg's bagpipe guts.
- Die Laughing: Subverted. While hanging for dear life, Constance (Lois) laughs as she mocks Stewie (Sherlock) for not figuring out the murder cases, but once she slips, she screams like a normal person falling to their deaths would.
- Disc-One Final Boss: Constance (Lois) is behind the murders, but she reveals before she dies that she was working for Moriarty (Peter).
- Disney Villain Death: Constance (Lois) suffers this.
- Disposable Sex Worker: Of an interesting Truth in Television Shown Their Work version, as the case is based of the Jack the Ripper killings and the Scottish Brute goes after prostitutes, however, Jack the Ripper wasn't that specific.
- "Eureka!" Moment: The cryptic message Constance (Lois) gives to Sherlock (Stewie) "He would be victorious," causes Sherlock to find out what's about to happen.
- Evil Redhead: What Constance (Lois) turns out to be.
- Femme Fatale: Constance (Lois) uses her feminine charms to keep Watson (Brian) and Sherlock (Stewie) distracted from finding out Moriarty's (Peter) plan.
- Lady in Red: Constance (Lois) spends much of her time wearing red or reddish clothes and she's a murderer for Professor Moriarty (Peter).
- Old-Timey Ankle Taboo: John Watson (a.k.a. Brian) is first attracted to Constance (a.k.a. Lois) when they pass on the street and she strategically bares her ankle to his gaze.
- Out-Gambitted: Stewie (Sherlock) manages to undo Moriarty's (Peter) carefully thought-out scheme with a Queen Victoria disguise.
- Shout-Out: The entire episode is one huge homage to the Sherlock Holmes story.
- In the title sequence, we see a dead Kenny (interestingly).
- There's a sequence that parodies The Love Boat
- Moriarty (Peter) states at the end that he's a teacher at Hogwarts, before revealing that he was joking but the episode should have been a parody of that instead of Sherlock Holmes.
- They Killed Kenny Again: The Trope Namer appears in the opening sequence, (literally) dead in the water.
