At the end of "Agents of S.H.I.E.L.D." Season 3, the show jumped forward in time by six months, only to reveal that Phil Coulson was no longer director and his team had splintered. What's more, Daisy (Chloe Bennet) is on the run from S.H.I.E.L.D., and Simmons (Elizabeth Henstridge) is working with Holden Radcliff alongside her partner and boyfriend Fitz. Both Bennet and Henstridge stopped by Comic-Con International in San Diego just one day after they started filming in order to discuss the upcoming season Season 4, its new tone, FitzSimmons' relationship and more.

"Even in the beginning at the table, there's a breath of fresh air being breathed," Bennet told CBR's Kiel Phegley. "It feels different! There's a new energy, and... everything's been kind of tucked away and pushed to the side."

"It's very exciting," Henstridge agreed. "Who knows what's going to be featured this season?"

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Asked if she was expecting FitzSimmons to finally get together, Henstridge said, "No! We spent all our time talking about how they were an old married couple or brother and sister, nothing kind of sexy. That was never going to happen. I think we convinced ourselves through convincing each other. We built up this whole thing: 'Absolutely no way.' And everybody told us, 'No, they'll never get together.' And then all of a sudden, we read the script and go, 'Oh, I guess they get it on, then!'"

"I think you have to earn those moments, and I think it had been quite a long time," she continued. "It was a journey. It was earned. We went through very many up and downs. But I like it! And we'll see what happens."

Bennet also addressed the show's new 10 pm timeslot as well as its newer -- and darker -- tone. "You know, I read the script. It definitely felt darker. It was darker, it's a little sexier, it's edgier, it's definitely more mature this year," she shared. "Again, a new fresh breath going into the season of sexy darkness."

"And the special effects have just kicked up again, which I don't know how they did that," Henstridge added.

Starring Clark Gregg, Chloe Bennet and Ming-Na Wen, "Agents of S.H.I.E.L.D" returns Tuesday, September 20 at 10 pm EST on ABC.