A massive snowstorm has hit New York City. The power is out and the roads are nearly impassible. Sherlock and Joan are called in to investigate a cell phone store robbery that has led to the death of a security guard, but soon realize that the burglary was designed to act as a distraction for the theft of a set of architectural blueprints. The plans are for E.R.O.C. - a building in New Jersey that houses the largest cash vault in the country. Believing that the thieves are likely to use the storm as cover for their heist, Sherlock and Joan work to stop the crime in the middle of a deadly blizzard. Sherlock offers Ms. Hudson, a stunning transgender woman who often acts as a 'kept woman' for the rich and powerful, a place to live in the brownstone while she gets back on her feet from her latest break-up.