Grey's Anatomy cast previews a 'lighter, funnier, and sexier' season 14

How do you keep a long-running medical drama fresh after 13 seasons? By literally blowing up the hospital at its center.

Grey's Anatomy did just that in the finale, paving the way for rebuilding — both at Grey Sloan Memorial and also within its ranks. That means everything from a new coat of paint to a fresh set of tech-dependent interns, and even the addition of a doc with a rather, ahem, interesting specialty. The updates lend themselves to a lot of comedy, bringing the show back to its rom-com roots. "The world has become such a dark place, and people really need a chance to laugh and have some relief," executive producer Krista Vernoff says.

"Since Derek Shepherd's death, the show and the hospital had to go through a certain period of mourning and darkness to deal with the aftermath and the fallout of that," says star Kevin McKidd, who also helms the second hour of the supersized season premiere. "Those times are behind the hospital. So it's really been fun to work on these scripts and really fit the tone back to that very much more dramedy place that the show used to have in those earlier seasons."

With that in mind, some of the comedy will originate from a new set of sub-interns — they're basically even younger than the Fab Five was when the show started back in 2005, though they're only here for a six-week rotation. "All of a sudden, young people come in and when we all saw young people come in 14 years ago with our hero tribe, we didn't see anything wrong with them," costar Jessica Capshaw says. "We were like, 'This is amazing, and they've all got their little personalities, but they're going to figure it out, and aren't they quirky and sweet?' But now we're all older and all that quirkiness doesn't seem as cute and funny, it seems like these people are morons."

GALLERY: Check out new Grey's Anatomy season 14 photos

However, the show isn't completely turning into a comedy. While costar Camilla Luddington concurs that season 14 is much "lighter, funnier, and sexier," the ABC medical drama "will always get heartache and heartbreak from relationship story lines, but also the patient story lines," she says. "You're going to need a bottle of wine, you're going to cry during Grey's Anatomy. Do I think there is a happier, lighter, sexier side also? Absolutely, and you'll see that just from the two-hour premiere."

Where Grey's is not so light is the show's most complicated love triangle yet. Just as Meredith (Ellen Pompeo) was opening up to a post-Derek dalliance with Nathan Riggs (Martin Henderson), his presumed-dead fiancée, Megan Hunt (recast as Abigail Spencer), who's also Owen's (McKidd) sister, was found alive after spending a decade held captive in Iraq by militants. "Reading between the lines, Megan presumes that Nathan is completely in love with Meredith," Henderson says, noting that the shared experience of Megan's return will bring Owen and Riggs closer. "A few days prior, he did want to pursue it, so he's trying to understand what Megan's presence in his life means."

Surprisingly, Meredith seems to be handling the situation quite well. "Meredith shows herself to be extremely understanding and very generous to both Nathan and Megan and I think that is a bit perplexing for Nathan because he maybe expected it to be even more awkward than it is, yet she seems to be quite copacetic with the whole thing," Henderson says. "But it begs the question, well, is she really?"

If you're having a hard time keeping track of all the ever-evoking relationships as Grey Sloan, we've updated our chart below.

Now let's talk about some of those couples:

April and Jackson

After taking notice of Jackson (Jesse Williams) and Maggie's (Kelly McCreary) chemistry, April (Sarah Drew) will be quick to confront her former husband about their unspoken romp in Montana. "Everything was okay if nobody else was in the mix in her mind. Now seeing there's real potential for him to move on, it's going to cause her to actually force the conversation," Drew says, noting it will make things awkward between April and Maggie at the top of the season. "It's all painful to be honest. She has a child with this man who also is her person and also her best friend, and seeing a new presence in her daughter's life, in her ex's life, is confusing and challenging. She needs to stop being in a state of limbo."

Amelia and Owen

Though Amelia (Caterina Scorsone) was there to support Owen upon discovering his presumed-dead sister, Megan, is still alive, "Amelia is in quite a surprising place when Megan returns, and it causes a lot of issues for Owen and Amelia," McKidd says. "It also causes issues for Owen's family." Their relationship is made more complicated by the return of Teddy (Kim Raver), who previously pined for Owen. "Him and Teddy are best friends from years and years ago, so that plays out in a very fun way."

RELATED: Here are the major cast changes coming in season 14 of Grey's Anatomy

Alex and Jo

Following a tumultuous season, Jo (Luddington) and Alex (Justin Chambers) may be on the road to recovery. That all depends, of course, on how Jo would react should she find out Alex tracked down her estranged and abusive husband, Paul (Matthew Morrison). "She would worry about Alex endangering both of them," Luddington says. "More than anything, she has been able to feel secure in her life because of her anonymity. If Alex has found him, she would feel like that's potentially breached, and it just becomes a very dangerous situation for her."

On another note, following Stephanie's (Jerrika Hinton) exit, Jo will be searching for her new person. "It's really hard for her because Jo doesn't have any family, and Stephanie was family to her," Luddington says. "She's not with Alex, and DeLuca's [Giacomo Gianniotti] a very odd situation, and she feels like she's lost that friendship because it's a little awkward right now. She's really looking for anyone to lean on, and one person that she does try to lean on is Ben [Jason George], which makes for some pretty fun scenes this season."

Arizona and…?

Following Eliza Minnick's exit, Arizona is on the prowl. "She's ready to have copious amounts of fun," Capshaw says. Could that fun involve the only new female doc, Carina (Stefania Spampinato), who just so happens to be the sister of Arizona's roommate, DeLuca? That would certainly lead to some juicy drama, but only time will tell!

Grey's Anatomy returns with a two-hour premiere on Thursday at 8 p.m. ET on ABC.