Olivia Benson’s reunion with Elliot Stabler brought an old investigation and unresolved tensions back into focus in the 600th episode of “Law & Order: Special Victims Unit,” which aired Nov. 12. Discussing the storyline, Mariska Hargitay explained why Benson needed to assert her authority and why an invitation from her former partner was never something she would accept. Spoilers follow for the milestone episode.

The case required Benson, played by Hargitay, to revisit work she and Stabler, played by Christopher Meloni, had done years earlier. Faced with the possibility that they had helped send the wrong man to prison, she persuaded him to return and assist with the investigation. Their renewed collaboration also forced her to confront how they had worked together.

Benson discovered that Stabler had excluded her from parts of the earlier investigation and assumed control, a dynamic she had permitted. Now a captain, she was unwilling to let that pattern reestablish itself. Hargitay described Stabler as an important influence on Benson’s development as a detective, making the question of how she moves beyond that influence central to the episode.

For Hargitay, the friction between the characters reflected the emotional complexity of a relationship shaped by loyalty, trust and shared experiences. She compared their ability to challenge each other to the tensions within a family. Their connection, she said, encompasses both what happened between them and the possibilities of what might have been. She also pointed to their dedication to one another as a reason audiences remain invested.

The story’s emphasis on Benson asserting herself was particularly significant to the actor. “It’s about a woman having her voice,” Hargitay said, adding that many women identify with that experience. She welcomed the opportunity to explore a substantial storyline involving the pair and said the aim was to portray a complicated relationship in a way viewers could recognize and respond to emotionally.

Hargitay said bringing Stabler back served both the audience’s interest in seeing the characters together and his continuing importance to Benson’s story. At the episode’s conclusion, he suggested that she take time off and join him on a trip for a few days. Although the episode had already established that Benson had leave available, Hargitay said accepting was never under consideration. “It’s not where they are now,” she explained, referring to both characters.