'Grey's Anatomy' Boss Teases 'Intense' Season 21 as Catherine Embraces Her Villain Role

Grey Sloan Memorial Hospital is not the best place to work when Grey's Anatomy returns for Season 21 on Thursday, September 26. Catherine Fox (Debbie Allen) fired three attendings, including the chief of surgery in the Season 20 finale after finding out how they were involved in helping Meredith (Ellen Pompeo) continue Alzheimer's Disease research that Catherine had previously forbidden.

Showrunner Meg Marinis told Parade that the vibe of the hospital is "intense" when the season kicks off and the drama from Meredith's research and Bailey (Chandra Wilson) standing up for the interns is far from over.

"We pick up right where Season 20 kind of left off. There is a lot obviously hanging in the balance. Everyone's job is on the line," Marinis explained. "Fans will get a kick out of seeing them rebuild and move forward. We deal with the aftermath of all the firings pretty immediately."

Marinis opened up more about what to expect now that Catherine is aware of Meredith's betrayal, familiar faces returning to the hospital, and what it was like telling Debbie Allen and Chandra Wilson about that jaw-dropping trailer slap.

Related: Everything to Know About Grey's Anatomy Season 21

When we talked last season, you teased how Catherine Fox would be a major adversary. What is she like in Season 21 now that she's actually been activated as a villain?
She's a very powerful person. When someone tries to challenge that, like Meredith, she clearly doesn't like it. There are going to be consequences from the first minute of the show.

What inspired you to bring Sydney Heron back after all of these years?
The writers have pitched her coming back multiple times since I've been a part of this staff. The previous times, it didn't feel right. When it was pitched in conjunction with the story that we're telling in the premiere, it fit perfectly. It brought a huge smile to my face. It was not my idea, it came from the writers' room, and we all jumped on the idea. The second that the lines were delivered at the table read, she delivered it exactly the way we had pictured and it got roaring laughter. I'm really excited for fans to see this treat.

What state is the residence program in now that Bailey's career is up in question? 
The program is also up in question. They put themselves on the line and she did as well. Catherine already threatened Lucas to have to remediate. The four of them are also freaked out because they just joined the team for fighting for him.

There is a jaw-dropping moment in the trailer where Bailey slaps Catherine. What were Debbie Allen and Chandra Wilson's reactions when they found out that scene was in coming?
Debbie was delighted. She was ready. Debbie is always ready for the drama and she loves to play the villain. She's a great villain. She leans into it and the villain part of Catherine is fun. She gives us so many things to play with. Chandra was a little bit like, "I'm doing what?" But Chandra is always game to tell the best story.

We know that Midori Frances and Jake Borelli are leaving this season. What can you tease about what's coming in their final episodes?
I can't tell you anything specific relating to their storylines because [of] spoilers. But they are stellar actors and stellar members of this cast. They are important members of the Grey's family. Their stories this year truly honor the characters that we built. People are going to be hooked into these stories from the very beginning. It's Grey's Anatomy. Our characters come and go here. Once you're part of the family, you're always part of the family.

Grey's Anatomy Season 21 premieres Thursday, September 26 at 10 p.m. ET on ABC.

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