‘The Lady Vanishes’ appears on PBS

care, fussing about her, ordering tea and chattering. The woman never stops chattering.

Soon, Miss Froy simply vanishes from the moving train.

Many people definitely saw her, though they deny it. People have their own reasons for lying. Iris is made out to be mad or — as is more favored for 1931 — a hysterical young woman in need of supervision.

Iris questions the passengers, trying to jog their memories about this most average-looking woman in the tweed suit. No luck. She grows increasingly agitated and eventually encounters a professor and his younger associate, Max (Tom Hughes), who is instantly smitten with her.

“He has traveled the world a little bit,” Hughes says of his character.

“She is like no other woman he has ever met. He has this ability to stand back and watch things, albeit with a youthful naivete. He has never met a girl with that much wealth — and (is) that complicated and that ballsy.”

Max wants to believe Iris, but all of the evidence indicates Iris is inventing Miss Froy. Iris is convinced Miss Froy met an evil end. People who she knows had seen them together refuse to acknowledge this truth.

But why? Why would a pleasant middle-aged lady vanish, and why would everyone who had seen her deny it?

A train is the perfect setting for such a mystery.

“I think they are kind of their own environment,” Middleton says. “It is a bit as if you are on a holiday or if you are on a set. It is almost an alternate reality, and it feels like nothing else exists outside of that. You are traveling. The one constant is your surroundings and the people on the train.”

“There is always danger, excitement and danger,” Middleton says. “Although if something bad happens, everything is more heightened in that sort of environment.”

Iris is furious as she questions people who she knows saw Miss Froy, and person after person simply does not want to get involved for personal reasons. One man is having an affair and doesn’t want authorities questioning him. One woman is rushing home because her son has died.

A doctor aboard the train wants to put Iris in a hospital, and though she refuses, he insists. He wants to sedate her, which she also refuses. Eventually, the doctor, who seems reasonable as Iris grows more agitated, manages to sneak in a sedative, using Max as an accomplice.

“I was shocked when Max spiked the soup because he seemed like the old all-American hero,” Hughes says. “Everything about him is upfront and optimistic. Everyone has their weaknesses. The doctor is an evil soul. He had his hand on the shoulder, whispering in Max’s ear.” It would be too much of a spoiler to relay what happened to Miss Froy and why.

It is, though, safe to say that this ending differs from the Hitchcock version.

“The reason Hitchcock would have adapted the original story is it is classic,” Middleton says. “It is a bit of everything — action, thriller, a mystery to it. A bit of every genre to it.”

“You can enjoy the costumes, and you can enjoy the ’30s setting, but ultimately it is about being young and slightly lost in the world and taking a risk and people taking advantage of that and trusting yourself when everyone else is questioning you — even yourself,” Hughes says. “It is a psychological thriller, far more than an edge-of-your seat thriller.”