[Warning: this story contains spoilers from Tuesday's episode of Agents of SHIELD, "4,722 Hours."]

Agents of SHIELD finally revealed what happened to its missing team member: Jemma Simmons (Elizabeth Henstridge) found love in a hopeless place.

After the Kree monolith mysteriously swallowed up the SHIELD scientist in the season two finale, viewers and her fellow SHIELD agents were left wondering what happened to her in the months since her disappearance. Tuesday's episode finally went back to that fateful moment from the finale to show Simmons' grueling experience on an alien planet for six months, and how she managed to fall in love with the only other human on the entire planet: a NASA astronaut named Will (Nikita's Dillon Casey).

ABC's Marvel series revealed that NASA tried to use the monolith for cheaper space exploration in the past, and Will's team was all killed off by a mysterious entity Will refers to as "Death," which was also written in Hebrew on the scroll Fitz (Iain De Caestecker) found during his search for Simmons. Will survived for over a decade alone on the planet before Simmons showed up, and it was only when Simmons believed she was stuck on the planet for good that she gave in to her feelings for Will.

The Hollywood Reporter spoke with Henstridge about filming the unique Simmons-centric episode, how this Will revelation affects Simmons' budding relationship with Fitz and how long it will take to get Will back after Simmons accidentally abandoned him when Fitz pulled her back through the portal.

The entire episode rests on your shoulders, instead of the show's ensemble. Was that daunting at all?

It was a lot more daunting when I first heard the idea, but then once we started filming it, I realized how much support there was. Yes, Simmons is featured more than usual and I had more lines to learn, but it was such a team effort. Once we got into it, it felt like a mountain we were all determined to climb together.

What did you think when you first heard the idea for the episode?

When I was told about it, I honestly thought that it wasn't going to happen. It's just such a risky idea to do, and it's so different from anything we've done before. I still can't believe it did get made.

When you finished reading the script, what was your first thought?

My main concern is how the fans are going to react. Are they going to hate Simmons now for what happened because of FitzSimmons? I was really worried.

How is Simmons' dynamic with Will different than her dynamic with Fitz?

Once their relationship turned romantic, it's very visceral. It's more primal and intense. That just comes from having to survive in a hostile environment, only having each other on the whole planet. The stakes are always so high, so it's more physical than her relationship with Fitz. FitzSimmons is a slow burn that's taken years and years, and they connected over intellect, whereas her and Will, it's an "us against the world" kind of thing.

Now that Fitz knows about Will, what does this mean for FitzSimmons' relationship going forward?

It puts a pin in their relationship for sure. Time is of the essence and they don't have time to dissect how they feel right now. They're focusing on getting Will back and doing the right, humane thing. The fact that Fitz is willing to help means there is still hope for their relationship. Whether that can ever be romantic now, I don't know. We're going to see them struggle with that, because Jemma never stopped loving Fitz. She just felt like she was never going to see him again. Her feelings never went away, but she now has feelings for another dude. It's an impossible situation for everyone. It's creating some brilliant scenes for Iain and I to have together.

How long will Fitz and Simmons be working on building a new portal? Is this going to be a storyline that pays off sooner rather than later, or is this going to be a slower burn?

It's going to take a while. There's a lot going on at SHIELD right now. And who knows if it is even going to work when we do eventually think we've found a solution.

What was it like filming Simmons' big breakdown scene when the portal closed before they could get the message in a bottle through it?

She truly had nothing left. It was a devastating moment. We've never seen her get to that point, where she questions, "What's the point in even living any more?" I never thought we'd see her get to that place. She always has that slight arrogance of intelligence, where if anyone can figure something out it's her. So it was nice and cathartic to finally see her crash down like that. It justifies her relationship with Will, too, because she was ready to end it all and he was the one who pulled her back from the brink. He is so different from Fitz, and Fitz is obviously her jam. He's a burly dude, a bit grumpy, doesn't like to talk very much, and just a real manly man, and that's not what she's been attracted to in the past. But their relationship was born out of her trying to get back to Fitz and that's what hurts the most.

What are you most excited to explore now that Fitz knows about Will and Simmons is determined to get him back?

I'm excited to explore Fitz and Simmons' relationship because it's so complicated right now. They're ferociously concentrating on the task at hand because if they waver for a second, someone is going to blow up. The tension between the two of them and the size of the elephant in the room is almost suffocating.

Agents of SHIELD airs Tuesdays at 9 p.m. on ABC.