Kaley Cuoco and Sam Claflin on New Mystery Drama (Exclusive)

[Warning: The following post contains spoilers for Vanished‘s series premiere, “Rosefinch.”]

A dream getaway becomes a nightmare at the start of MGM+’s new thriller miniseries Vanished. The first leg of the four-part journey has arrived on the streamer, and it finds Alice Monroe (Kaley Cuoco) searching for answers after her beloved boyfriend of four years, Tom (Sam Claflin), suddenly disappears during a train ride across the countryside in France.

In the premiere, before his disappearance, we see that Alice and Tom are very much in love, even if their careers keep them apart most of the time. She’s an archaeologist who’s been in Toronto, and he’s a humanitarian aid worker who’s been stationed in Jordan all the while. Their trip to France together is one of many they’ve taken across the world to reconnect over the years, but she wants a change: She’s been offered a job at Princeton and wants him to move with her there. After a beat, he accepts.

Claflin told TV Insider that despite the bit of hesitation there, Tom is very serious about taking her up on the offer. “I think he 100% believes that is going to happen,” he said of the two moving together to New Jersey all of a sudden.

In the morning light, Tom and Alice head out to a hotel in Arles that they’ve long been aspiring to visit. Along the journey, things are peaceful at first — comedic, even, as Tom whips out a rather regrettable Hans Landa impression along the ride just for kicks.

Of that impression, Claflin said, “No one can do it like Christoph Waltz. But I did sit and watch that clip on YouTube more times than I wish to admit, trying to perfect it, but it was very, very difficult… His performance in [Inglourious Basterds] is iconic, and I can only laugh at myself at my terrible attempt. I think that’s the point; it’s meant to be terrible.”

After Tom gets a mystery call and walks away to answer it, he never returns to his seat, and Alice is left scrambling throughout the cars trying to find him. A stranger named Helene (Karin Viard) is exceedingly — even curiously so — willing to help, but the conductor, a man named Geroux, shuts down her search for more clues onboard the train.

After the next stop, Alice gets off and, after the police refuse to help her, uses her archaeological instincts to start an investigation of her own. She journeys back to a bridge they passed just before an unexplained stop between stations and sifts through literal dirt for clues before a train zips by right next to her, scaring the daylights out of her.

MGM+

Her petrified reaction, Cuoco revealed, was very, very real. “I believe that’s the bullet train… That train goes, I want to say, every 15 minutes, something like that. So you can’t plan it. You can’t ask the train to do [what you need]. So we went there to shoot it, and they wanted this shot of me, of the train really going by, and because it was happening in real time, there was no way to rehearse it. You either did it, or you didn’t.”

The actress continued, “They kept saying to me, ‘Please be ready. It’s really loud.’ And my stunt double was there, who I worked with for years, and she had gone up earlier in the day and stood there, and she was like, ‘Kaley, it feels like it’s going to take you.’ I mean, I could have reached my hand out and probably touched that train. And I said I wanted to do it, even though I was extremely scared. So I went up there, and they were waiting. The countdown was coming… So the train is about to come by, and I’m like, ‘I know the train is going to come by, but I need to look like I didn’t know the train was going to come by.’ … I’m telling you [it was] the loudest, scariest, unbelievable feeling. And when it went by, that reaction, everything about that was real. I couldn’t believe I was that close to it, and I just did that. And when we called ‘cut,’ I just started tearing up, and I was just so… I felt so small in that moment. It was kind of unbelievable. It brought me back down to the planet.”

After that, when the police are once again unhelpful, Alice decides to give her new friend Helene a call and learns something very disturbing: Helene believes the conductor had something to do with Tom’s disappearance.

Even weirder? Alice discovers that the new tattoo Tom was sporting, of a Sinai Rosefinch, matches one sported by his pretty former relief coworker on social media.

Vanished, Sundays, 9/8c, MGM+