The Time Team gears up for their final mission.

Timeless returns from the dead once again for a special series finale, airing Thursday at 8 p.m. ET/PT on NBC, which promises to properly conclude the show’s biggest mysteries. The time-travel drama, canceled twice and resurrected twice, has never had a huge following, but its loyal fanbase is passionate and loud. The fans, who endearingly call themselves Clockblockers, have spent their own time and money keeping the show alive, whether it be digital billboards in Times Square to personalized cupcakes for the cast to banners imploring the powers that be to #SaveTimeless.

“Everything just feels like a bonus. What’s interesting is it’s satisfying and unsatisfying, as all good endings should be because you want more, but satisfying because we address some of the open storylines,” Abigail Spencer told ET of the final two episodes during an exclusive set visit in early November. “It’s really the highlights of what would’ve gone on a few more seasons in and trying to put that all into a two-hour movie. A lot has gotten more wrapped up. If we had gotten a season three, I think we probably would’ve spent a season exploring the Lucy and Wyatt that you met at the end of season two.”

The series’ final two episodes, appropriately titled “The Miracle of Christmas” (because this truly is a holiday miracle!), picks up moments after the jaw-dropping sophomore closer, when Future Lucy and Wyatt blasted through five years into their past (aka our present day), with a presumed blueprint to save Rufus. There are notable callbacks to the pilot and the past two seasons, including a touching closing montage and the real story behind Lucy’s journal, that will surely make even the iciest of hearts thaw just a little bit.

The cast all admitted that Timeless has been a wholly unique experience, both in front of and behind the camera, in part due to the perennial bubble status of the show. And while these final two episodes have been billed as the end, some aren’t so sure, citing the unmined potential for rich storytelling. 

“Who knows? Everyone’s like ‘Maybe you’ll do more!’ Like, I didn’t know I was going to be here,” Spencer, who next stars in Hulu’s Reprisal drama project, said with a laugh. “The first time we got canceled and then picked up, I was asleep when that happened. And then the second time, when I heard about this, I was over in London galavanting about, not a care in the world [and then], Wait, what?! We’re all moving onto other projects and everyone’s doing shorter orders, so nothing’s off the table.”

“It doesn’t feel like an end, because fan passion is so high and it’s never been higher,” Matt Lanter told ET. “If it airs and people show up and watch it live, that’s the most important thing. If anyone wants to give Timeless any sort of a chance after this movie, they have to watch it live. If people really show up, our chances increase dramatically. Obviously, all the actors have to be free but who knows? I’m sure we can figure that out.”

Goran Visnjic was also cautiously optimistic, confessing that the ups and downs he’s endured over the course of the show’s history have trained him not to completely close the book on the world of Timeless. “In all honesty, I really love the show. I’m hoping somehow it’s not [the end],” he told ET. “Even if they definitively say it’s done, I’m still not going to believe it.”

Even so, the series finale does have a finality to it, which gave the cast some solace in knowing that if this truly is it, they at least got to see their characters’ arcs through to some sort of finite end. But what could be still lingers.

“I thought it was the end twice. I think we should be in the Guinness Book of World Records for most cancellations and most pickups. It’s insane,” Spencer mused. “I’ve seen shows get movies 10 years later or picked up by another network, but I’ve never seen getting canceled twice and picked up by the network twice. Honestly, if the movie does amazing and 20 million people watch it, they’ll want to do another one so it’s really up to the devoted fans.”

“It’s bittersweet. It is great that NBC’s doing this and giving us the opportunity to wrap it up,” Lanter said. “So many people love it. We tell so many great stories and the potential is so unlimited with where we can go in history and maybe even the future, but we don’t even need to, because the well is so deep for historical events we can go to. It has a lot more potential. We have a lot more stories to tell, so it’s sad that we might not get to tell them. There are a lot more interesting things we can do. It’s limitless. When we were first shooting the pilot, we were all looking around going like, ‘This could go on for a long, long time if it catches on,’ because the potential is just limitless. But turns out…”

Added Visnjic: “I was hoping to see many, many things and I had crazy ideas where the show could go. Unfortunately, we’re not going to see that. Or maybe we will.”

For Spencer, the leader of the Timeless crewthere is one scene in particular near the end of the series finale that got her misty-eyed because it harkened back to a memory she had of the first day filming the series’ very first episode.

“Rufus has a line, ‘It started with the three of us. We’re going to finish with the three of us,’ so viscerally it felt like we were shooting the pilot in Vancouver and we were shooting our first scene,” she reminisced of that moment in early 2016 with Lanter and Malcolm Barrett. “It’s freezing and we don’t really know each other. All of a sudden we looked at each other and said, ‘Moment before,’ and we all jumped and did this little dance at the same time. And I was like, ‘OK, this is going to be fine.'”

“Much like our characters, it feels like the three of us have been through battle together. We’ve traveled the country. We’ve done press together. My relationship with Malcolm and Matt has carried me through — what we’ve done with the show, how difficult the show is to execute, the fact that we all like each other and enjoy each other and constantly keep trying to raise the bar for our work.”

Timeless airs its two-hour series finale on Thursday, Dec. 20 at 8 p.m. ET/PT on NBC.

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