EXCLUSIVE: Agents Of S.H.I.E.L.D's Elizabeth Henstridge Talks FitzSimmons' Future And The Alien Planet's Evil

SPOILERS for tonight's episode of Marvel's Agents of S.H.I.E.L.D.follow

Tonight's episode of Marvel's Agents of S.H.I.E.L.D., "4,722 Hours," focused on Jemma Simmons, played by Elizabeth Henstridge, and how she survived six months on an alien planet.

The episode revealed that Simmons wasn't alone. She met an astronaut, Will, who has been trapped on the alien world for 15 years. After months depending on each for support and helping each other survive, they entered a romantic relationship. But when Simmons was finally rescued, Will was left behind.

But there something else on that planet, a malevolent presence unlike anything we've seen before on the show, and one devious and powerful enough to drive NASA scientists to suicide.

We spoke to Henstridge about the episode prior to its airing, and we asked her what it means for Simmons' relationship with Fitz, and what she knows about the mysterious alien evil.

So now that Fitz knows Simmons' story, how do you think this effects their relationship going forward?

EH: Oh god, it's such a tough one. I think they're both now – she's so beyond grateful that Fitz is going to help her with getting Will back. The trouble is that she doesn't even know Will is alive at this point, because she hears the gunshot, and who knows what has happened to him. She's so confused, and the love that Fitz is showing for her by helping her with this task, you know, it's overwhelming. We're definitely going to see that tension between the two of them. Right now, her feelings for Fitz, and his feelings for her, they're just putting them aside to try and concentrate on this task, and that's what they do best. They work very well together, but this is a huge obstacle, and a massive elephant in the room. At the moment, their relationship is in tatters, but Fitz has enough unconditional love for Simmons to help her with this. He's a good guy, in the end of it, and he realizes that somebody needs help, and he's willing to do that. But their relationship, we can't see a path to them being good together again for a while. But for right now, they're putting all that aside and just concentrating on doing the right thing, which is trying to get this man that saved Simmons' life back home.

This evil presence on the planet with you is unlike anything we've seen on the show before. How was it described to you, in the context of the episode?

EH: I learned of it from reading the script, and everything that happens on this planet is going to affect where our season goes. There wasn't much explanation given to me, as to what it is, and I think a lot of that is because Simmons finds out through Will, and then doesn't really believe it, and then experiences it, and then does believe it. So that's something she's going to be cautious of, and warning the team of. The bottom line is we don't know what it is, and we haven't dealt with anything like this before. We will find out much more about that, and its true dangerous potential. But in terms of what I was forewarned about before, all my information just comes from the script.

Marvel's Agents of S.H.I.E.L.D. airs Tuesdays at 9 p.m. ET on ABC.