Agents of SHIELD's Fitz and Simmons physically survived HYDRA, but will their partnership?

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Ward left the science wonder twins to die at the bottom of the ocean, and Fitz (Iain De Caestecker) nearly gave his life to Simmons (Elizabeth Henstridge) in the season 1 finale. The engineering genius did, however, confess his love for his partner, and the pair will need to address their changing relationship once Fitz is on the mend.

"The beauty of what [Fitz said to Simmons trapped underwater] is it makes for lots of complicated feelings," said executive producer Jeff Bell, according to TV Line. "I'd be curious to see how things will be different or the same now."

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Henstridge told Comicpalooza attendees that Fitz will always be her "main priority," but the agent will have to deal with her own version of survivor guilt.

"She's changed a lot from what happened at the end of last season, and her relationship with Fitz is obviously strained and fractured due to her guilt that she feels for taking the oxygen and him having no air," Henstridge explained to Buddy TV at the 2014 San Diego Comic-Con. "So their relationship is something that we're going to explore more, and the undertones of guilt and regret."

Click the video below to take a look back at FitzSimmons highpoints from season 1 and get a glimpse of the pair in the season 2 premiere.

Find out more when Agents of SHIELD returns to ABC on Sept. 23 at 9 p.m. ET.