Season 14 of Grey's Anatomy may have taken on a lighter tone but Thursday night saw the show tackle one of its heaviest topics to date: domestic violence. The episode's title, "1-800-799-7233," bears the number for the National Domestic Violence Hotline and, per Camilla Luddington, was suggested by Giacomo Gianniotti

Picking up right where the fall finale left off, Grey Sloan is still in the middle of a crisis after a hacker hijacked the hospital's computers, forcing doctors to improvise alternative treatments for their patients. However, Jo (Luddington) experiences a crisis of her own when she ends up face-to-face with her abusive ex — a brilliant doctor by the name of Paul Stadler (Matthew Morrison).

"It turns her entire world upside down," Luddington told TV Guide of the tense encounter. "In that moment, nothing else matters and it's just her and Paul Stadler. She's in complete shock and I don't think she knows in that instance what to think or what to even do."

Paul showed up unannounced to finalize his divorce from Jo, but it looks like he may have also weaseled his way back into her world despite her massive efforts to escape him. Changing her name from Brooke Stadler, Jo crafted an entirely new life for herself and his presence now threatens that. "He's infiltrating a world that she didn't think he would or hoped he wouldn't," said Luddington.

Grey's Anatomy's Ellen Pompeo Is Now the Highest Paid Dramatic TV Actress

Things are further complicated by the fact that Paul didn't come alone. He brought along his new fiancée, Jenny (Bethany Joy Lenz), who Jo worries may also be a victim of Paul's abuse. With assistance from Meredith (Ellen Pompeo), Arizona (Jessica Capshaw) and Alex (Justin Chambers), she gets Jenny alone and offers to help her escape the potentially violent relationship, but not before detailing her own harrowing experience with Paul.

"We haven't yet heard her explicitly describe in detail what happened to her, exactly how he would abuse her," Luddington added. "So I think her saying the words may have been the first time she's ever said that out loud to anybody."

But the touching moment backfires when Jenny outs Jo to an incensed Paul who then threatens the surgical resident. While her failed effort to reach out may have left her less inclined to share her story again, it also gave Jo a newfound strength. "I don't know if moving forward, she would necessarily feel so open to describe to someone again. But I do think it's the beginning of Jo finding her voice," Luddington explained. "Even though he threatened her, I think we'll see [her] grow in confidence."

Part of that has to do with her support system made up of Alex and now Meredith and Arizona as well. Meredith standing with Jo and telling her, "I know who you are" not only marked a turning point in their sometimes tumultuous relationship, but according to Luddington, also gives Jo hope that she can move forward with her life.

"Never before has she been believed but these people around her [Meredith, Alex and Arizona], they believe her. I don't think she feels that she is silenced anymore," she added.

But now that Paul has turned up at Grey Sloan as the victim of a hit-and-run, the question remains: Were Alex and Jo behind it? Or did Jenny exact her revenge on her abusive partner?

Grey's Anatomy airs Thursdays at 8/7c on ABC.

Camilla Luddington, Grey's AnatomyCamilla Luddington, Grey's Anatomy