In the first episode of a two-part event, Watson begins her new job as an in-house investigator for an insurance firm. However, her attention shifts to a case that is personal for both her and Holmes when they join forces to eliminate an imminent threat to Kitty.

When a debt collector is murdered, Holmes and Watson attempt to narrow down a suspect pool of thousands of consumers who owed the man money. Meanwhile, Watson's relationship with Andrew progresses when he asks her to meet his father for the first time.