SPOILER WARNING: This article contains major spoilers for "4,722 Hours," tonight's episode of "Agents of S.H.I.E.L.D."


After five tense episodes of Marvel's "Agents of S.H.I.E.L.D.", Agent Jemma Simmons' secret is out: she wasn't the only one who survived the trip through the Monolith. During her six-month interplanetary ordeal, she met Will Daniels (Dillon Casey), an astronaut who volunteered to study the world on the other side of the wormhole way back in 2001. Not only that, Simmons and Daniels fell in love when all hope seemed lost, culminating in Daniels' sacrifice, which allowed Simmons the time to get safely back to Earth. Now, Simmons is desperate to rescue the man who saved her.

RELATED: "Agents of SHIELD's" Henstridge Opens Up on Simmons' Extraterrestrial Adventure

Star Elizabeth Henstridge discussed the episode with CBR News, weighing in on Simmons' motivations as well as her admiration for Fitz (Iain de Caestecker) after he made a difficult, selfless decision to help save Daniels. Henstridge also briefly touched upon the nameless It, the dust storm-producing monster that ruled the barren wasteland she and Daniels survived.

CBR News: Just how desperate do you think Simmons is to rescue Will, and does she have any other motives for returning?

Elizabeth Henstridge: No, he's the sole motive. I think she doesn't want to see that planet ever again and the fact that we don't know what It is -- It's killed everybody else apart from Will and Simmons, so going back is extremely dangerous. Honestly, I think she's tried to compartmentalize it, like, "Well, that was then, now I'm back and I need to concentrate on being back" and she just can't. She can't live with herself without trying to get him back to safety because he saved her life. Will is her sole focus right now.

Will Fitz's reaction to Simmons' story at the end of the episode change the way she views him?

Oh, for sure! I think she's always known how much he cares about her. Seeing how selfless he is in saying yes... the aim is to get Will back, and -- if they do get Will back -- that makes things very difficult and painful for Fitz. The best thing for him would be to say, "Oh, no, it's just impossible, there's no way." But he doesn't do that. He has such an unconditional love for Simmons and he just is a good dude and will always do what's right morally. I think, in that moment, she just can't believe he is so no-nonsense about it. He's already made his mind up and he's getting on with it. There's no kind of melodrama. His love for her is just so strong he doesn't even question it... When I read that, I was just in lots of tears.

Starring Clark Gregg, Chloe Bennet and Ming-Na Wen, "Agents of S.H.I.E.L.D." airs Tuesdays at 9 P.M. EST on ABC.