Sherlock and Watson investigate a robbery, only to be hampered by a snowstorm.
Tropes:
- Accent Relapse: "Alysa Darvin" speaks with a perfect American accent until Bell reveals they've discovered her true identity of Elle Bastien. Knowing she's caught she reverts to a thick French accent.
- Admiring the Abomination: Sherlock says the thieves' crime is at once ingenious, audacious, and has been carefully planned years in advance. If they hadn't inadvertently killed someone, he'd be tempted to let them get away with it.
- Awesomeness by Analysis: Bell catches Darvin/Bastien when he notices a long blonde hair on her coat even though she has dark hair. She claims it's from a friend whose coat she borrowed but when Bell holds the hair up to the light it melts, revealing it as a fake hair from a wig that matches the one worn by the thief he's pursuing. Sherlock's methods appear to be rubbing off on him.
- Counterfeit Cash: Ingeniously subverted. The thieves replace bills that were meant to be shredded at the Federal Reserve with paper copies, while taking the real stuff. No one but Sherlock and Joan would think to look closely at bales of shredded money, destined for the county dump, to see if they were fake. note
- Pet the Dog: After asking the homeless man where he got the stolen phones Sherlock gives him some money to get a hotel room so he won't be outside for the rest of the blizzard. This moment was requested by Jonny Lee Miller who wanted to show a more caring side to Sherlock.
- Planning with Props: While trying to work out the thieves' getaway route Sherlock uses Clyde the tortoise to represent the ambulance and some padlocks to represent checkpoints. When he explains his conclusion to Gregson he swaps Clyde for a stapler and the padlocks for stickers.
- Scout-Out: After Joan compliments her for building a wood fire, Ms. Hudson says she got a merit badge for it as a child.
- Trojan Ambulance: A complex plan to steal a vast sum of money in worn banknotes intended for destruction involves the use of a stolen ambulance as a getaway vehicle. The thieves even set up a legitimate ambulance to be mistaken by the police for their getaway vehicle as a distraction.
