'Quantum Leap' Stars Tease Season 1 Finale and 'Huge' Cliffhanger (Exclusive)

ET was on the set with stars Raymond Lee, Ernie Hudson and Caitlin Bassett for the freshman finale.

Quantum Leap is leaping back to the beginning.

NBC's sci-fi action drama closes out its freshman season Monday with Ben Song (Raymond Lee) going back to 2018, answering the question of why he leapt in the first place (see: to save Addison in the future) and how the team got to where they are now. ET's Will Marfuggi was with the cast on the Quantum Leap set in February while they filmed the season's final episode and geared up for the upcoming sophomore run.

"We find Ben at the top of this episode having leapt into Ben of the past, 2018 Ben," Lee told ET. "This is something that we haven't seen before because we haven't had an opportunity for Ben to be in the headquarters before. So we're going to get to see something really fun just in terms of team dynamics. You've never seen us all in one space. And boy, we leap everywhere in this episode time-wise."

Co-star Ernie Hudson, who plays the head of the Quantum Leap project, Herbert "Magic" Williams, confirmed the season-long mystery of how they got to this point is acknowledged and addressed.

"In this first season, we finally realize this is why he did what he did," Hudson teased. "The choices you make possibly could have been handled differently, but he didn't consult anyone because we do that sometimes -- we take it upon ourselves to fix things. But it sets a lot of things in motion. And in this final episode, we see the impact of what he did and if it gets resolved, how it gets resolved... The ripple goes everywhere. So even if you can go back and change that, you didn't change all this other stuff that you set in motion."

Of course, nothing in the world of Quantum Leap goes without major hiccups and the finale, Hudson warns, is no different.

"This cliffhanger is huge [on a] scale of one to 10," he previews. "In terms of time travel, it is definitely a 10 because we built everything to finally get to a place of understanding [and] we fall off that cliff and there's no understanding. We don't know what's going to happen and how it's going to resolve itself. Just have trust that it will in time."

The 'Quantum Leap' cast attend WonderCon 2023 on Saturday, March 25. - David Yeh/NBC

But Lee played more coy, only saying with regard to a finale cliffhanger, "It could be and also, it might not be... There's some sort of resolution just in terms of we've left the audience with a lot of loose ends to tie, and as promised, we're tying up a lot of those. But as far as specific journeys for individual characters, we're leaving everything up in the air."

Even so, Lee says his character, Ben, is in "quite a bit" of peril throughout the hour. "I've lost my voice twice throughout shooting this episode...," the actor shared. "But also maybe perhaps I've felt things as an actor I've never felt before throughout the course of this episode."

"It's really well-written, really well-crafted. It's one of the best scripts I've ever read, period. And it's only something that you could do on a show like ours that has to do with science fiction, time travel and the specific theme of leaping into another person's body. And you can only see that on Quantum Leap," Lee teased.

The cast reflected on the impact the show has made on fans, sharing memorable real-life encounters that they've had since the reboot of the '90s Scott Bakula series launched in September.

"It's been incredibly buoying and encouraging," co-star Caitlin Bassett, who plays Ben's "observer" Addison. "Obviously when you have a beloved piece of IP, there's a lot of pressure. And of course we've changed a lot of things. I know there's definitely some people who miss certain elements of the first one. But what's been really wonderful -- and I think it speaks to the fans of this show and the kind of people that the show really brings in -- the energy that it gives is they've been really open to, 'OK, well, it's not the old one, but let's see what they do with it.' And I'm just so appreciative for the fans of this show to stick with us."

Lee recalled bumping into a group of fans while he was furniture shopping: "At IKEA the other day, there were three lovely folks in their teens and it's that energy of, 'Hey, we love your show.' I haven't gotten that in my career yet. And so that was a really nice feeling."

As for how viewers will feel when they tune in to the finale, Lee has high hopes. "I think audiences will be satisfied. I sure was reading it," he said.

The Quantum Leap finale airs Monday, April 3 at 10 p.m. ET/PT on NBC.