While Kitty tries to find a runaway teen, Sherlock and Joan work a case in which the murder of a brilliant bioengineer looks to be at the hands of a drug cartel. Also, Joan makes a major life decision but worries it will impact Sherlock negatively, not knowing that Sherlock has big news of his own.
Elenco: Jonny Lee Miller , Lucy Liu , Jon Michael Hill , Aidan Quinn , John Noble , Natalie Dormer , Ophelia Lovibond , Rhys Ifans , Sean Pertwee .