It's a new dawn for Meredith Grey (Ellen Pompeo) on Season 12 of Grey's Anatomy, which kicks off Thursday (8/7c, ABC). Creator Shonda Rhimes has emphasized that this will be a lighter season of the ABC drama, following the sudden death of Meredith's husband Derek (Patrick Dempsey) at the end of last season. But that may not be the case for everybody. This wouldn't beGrey's if there wasn't a little bit of angst, right?

Here are four upcoming plot lines that will lead to a fair share of drama this season:

1. The new chief Deciding who will be the new chief of surgery is putting a damper on Webber (James Pickens Jr.) and Catherine's (Debbie Allen) honeymoon period as newlyweds. Webber is backing Bailey (Chandra Wilson), while Catherine brings in her own pick for who should run the show in the premiere (guest star Joey Lauren Adams). "There's a real bone of contention between them," Allen, who was also promoted to an executive producer this season, tells "They have very strong differences of opinion about it, and Catherine certainly is going to go to bat for what she thinks is right for the hospital. They have differences of opinion, and those differences flare up in the very first episode."

Grey's Anatomy: Meredith will experience a "rebirth" after Derek's death

2. April's enlistment Also having relationship woes are Jackson (Jesse Williams) and April (Sarah Drew), whose relationship was left in limbo at the end of last season when April said she wanted to re-enlist. When Season 12 picks up, she's in the midst of another overseas medical tour. "The ramifications are big," Allen says. "They both left with such open wounds, so hurt and wounded from the loss of their child, and just the inability for him to penetrate her walls or to even comfort her. It was just almost impossible for him. ... Nothing is going to get resolved any time soon."

3. More interns - and more bad relationship decisionsWe'll get to know some of the new interns who were introduced last season, and additional ones will be brought on in Episode 4. And, needless to say, viewers can expect some sparks to fly among the new and old characters. "They're getting fleshed out now, and you're just getting a better sense of where they are as doctors," according to Allen. "What are their dilemmas? What are their strengths, their weaknesses? What are the relationships between them and some of the existing cast? There's always that love interest. There's always some of that going on. Forbidden fruit, if you will."

Fall TV Preview: Get scoop on Grey's Anatomy and other returning shows

4. New love(s) for Calzona Callie (Sara Ramirez) and Arizona (Jessica Capshaw) will both get back into the dating game this season, but that leads to some surprising feelings of jealousy and tension for the former couple as they continue to co-parent Sofia. "When two people have had this kind of committed, tumultuous relationship - and it has been that - and then finally they go their separate ways, there's still love there," Allen notes. "Even though you've moved on, you're always going to go, 'Well, who is she with? And what is that?' There's going to be questions about that and feelings. Because when there's love, there's always feelings. When people have children together, they can't divorce totally. You still have to see them, whether you can't stand them or not."

5. A different side of Maggie With Maggie (Kelly McCreary), Amelia (Caterina Scorsone) and Meredith all sharing a house, we'll get to see Maggie come out of her shell a little bit. Does that mean a new love interest? Maybe, but she's got a ways to go to get there. "It's hard to be with anybody when you can't be with yourself," Allen says. "Maggie's discovering herself. She's always been this brilliant doctor, a very smart genius. ... But there's a part of her life that was probably not so developed, her social skills, what that is. So, she's just trying to figure it out. There's a real period here of self-discovery."

Grey's Anatomy returns Thursday at 8/7c on ABC. Will you watch?