Sherlock (Jonny Lee Miller) and Joan (Lucy Liu) will take on a case involving a retired FBI agent in the upcoming episode of the CBS series "Elementary."

In "Miss Taken," CarterMatt reports that the pair's preliminary investigation will trigger a deeper probe on the night the ex-operative was murdered. It appears that his death is somehow linked to a case he previously worked on but was forced to leave unsolved. This will prompt Sherlock and Joan to look into his past to determine who has the motive to silence him. Meanwhile, Sherlock will have the pleasure of meeting a member of Joan's family.

Her stepfather (John Heard) has just completed what is supposed to be a sure-win crime novel and is bursting to tell Joan the news. Unfortunately, she will not be amused, especially after learning that the writer based his "masterpiece" on her detective work without telling her. It appears that Sherlock will not be the only one to have family problems, as viewers will get to witness Joan's strained relationship with her mother's new husband.

The introduction of Joan's stepdad was first announced by series executive producer Rob Doherty via TV Guide. He said that the two also have "a pretty complicated relationship," just like Sherlock and his estranged father Morland (John Noble). This theme would reportedly be established during the first half of the season.

In the past episodes, viewers saw Morland's continued attempt to make amends with his son. Sherlock still has not forgiven his old man for sending him to rehab. He particularly could not forget that Morland was an absentee father for most of his life. Before the series went on winter hiatus, Morland tried yet again to get on Sherlock's good side, this time by using his considerable resources to help him solve a case.

"Elementary" season 4, episode 7 will air on Thursday, Jan. 7, at 10 p.m. EST on CBS.