The death of someone Holmes (Jonny Lee Miller) worked with in London brings Kitty (Ophelia Lovibond) back to New York believing that the apparently death of natural causes is actually the third of such crimes hiding three murders tied to a case she and Sherlock worked in London. While initially skeptical, Holmes and Watson (Lucy Liu) begin to agree with Kitty's assessment which suggests the defendant (Michael Patrick Thornton) involved in the case is likely responsible. And then events take an unexpected turn.
I've missed Kitty, Holmes' protege who the show spent most of an entire season developing. She returns with a couple of surprises. One, involving her newborn baby, is a shock to Sherlock and Watson. The other, the ease which she smooths over events with Gregson (Aidan Quinn), is a shock to the audience. Just what exactly she said to get back into the Captain's good graces is a mystery the show's writers seem willing to leave unsolved. As for the case of the week, the death of the group's leading suspect and the arrival of government agents inside the brownstone leads to several new questions as the episode ends on a cliffhanger. Whatever is actually going on it's more complicated than Holmes or Kitty suspected. That should mean Kitty will be staying around a little longer than she initially planned.