Watch: 'Grey's Anatomy' Season 21 trailer: Ellen Pompeo's Meredith fights with Debbie Allen's Catherine

Sept. 19 (UPI) -- The doctors of Grey Sloan Memorial continue to experience personal and medical drama in Season 21 of Grey's Anatomy.

The long-running series will return on Sept. 26 on ABC at 10 p.m. EDT.

Catherine Fox ( Debbie Allen ), who fired several doctors in Season 20, continues to cause turmoil and continues to butt heads with Meredith Grey ( Ellen Pompeo ). Miranda Bailey ( Chandra Wilson ) is seen slapping Catherine across the face due to their issues.

Jessie Williams returns as series favorite Jackson Avery this season and tells Meredith in the trailer to apologize to his mother, Catherine.

Kali Rocha returns to the series at Sydney Heron -- 17 years after she first appeared.

The romance between Jo (Camilla Luddington) and Link (Chris Carmack) will be in the spotlight this season. At the same time, Teddy Altman ( Kim Raver ) will deal with her role as Chief of Surgery and her issues with Owen Hunt (Kevin McKidd).

James Pickens Jr., Catherine Scorsone, Anthony Hill, Alexis Floyd, Harry Shum Jr., Adelaide Kane, Niko Terho, Jason George, Jake Borelli, Midori Francis, Scott Speedman and Natalie Morales are all set to return.