On the Season 21 premiere of Grey's Anatomy, Meredith ( Ellen Pompeo) thwarted Catherine's ( Debbie Allen) plans. But that doesn't mean we can expect a one-dimensional villain. Showrunner Meg Marini previewed the Catherine drama to come, as well as other high-stakes conflicts, to The Hollywood Reporter.

The latest premiere of the longest-running US medical drama was dedicated to Stephanie Leifer and, while casual fans of the long-running medical drama might not be aware of who she is, the tribute was a moving moment as Leifer was an instrumental figure in the show’s enduring success.

The Season 21 premiere of "Grey's Anatomy" will air on ABC. Fans can also stream the episode on Hulu Friday morning. The first 20 seasons of the series are available to stream on both Netflix and Hulu. Netflix typically adds new seasons of "Grey's Anatomy" after a season wraps up and the same is expected for Season 21.