Ep 1. Locum

In Law & Order: Special Victims Unit season 12 episode 1, titled "Locum," the audience is introduced to a new character, Dr. Maureen Stabler, who is filling in for Olivia Benson while she is on leave. Dr. Stabler, who is the wife of Detective Elliot Stabler, is a forensic psychiatrist who is hired to evaluate a rape victim and determine whether or not she is fit to stand trial against her attacker.

The victim in question is a young woman named Amanda who was brutally assaulted and left for dead in a park. Her attacker is a wealthy businessman named Byron Marks who has a high-powered legal team defending him. The SVU team quickly realizes that this case is going to be a tough one as Marks has powerful connections and is willing to do whatever it takes to clear his name.

As Dr. Stabler works with Amanda to assess her mental state, the SVU team digs deeper into the case and uncovers some disturbing evidence that suggests Marks has done this before. The team also discovers that he has a history of paying off his victims to keep them quiet.

As the trial approaches, tensions run high as Marks' legal team fights tooth and nail to discredit Amanda's testimony. Dr. Stabler is forced to testify in court, and her testimony ultimately helps the SVU team secure a conviction against Marks.

Throughout the episode, we also see Detective Stabler struggling with his own personal demons as he deals with the aftermath of his wife's assault at the end of the previous season. He finds solace and understanding in his new partner, Detective Serena Stevens, who he becomes fast friends with.

Overall, "Locum" is an intense and emotional episode of Law & Order: Special Victims Unit that tackles important issues related to sexual assault and the legal system's handling of these cases. The addition of Dr. Stabler as a character adds a new dynamic to the show and sets the stage for future episodes to come.