Agatha

Agatha Christie receives a silver cup engraved for her husband Archie, who shows clear disdain. The couple then walk to a publicity event for her new novel, The Murder of Roger Ackroyd, while being tailed by a persistent American reporter, Wally Stanton.

The next morning, Archie confronts Agatha and demands a divorce, admitting that he loves his secretary, Nancy Neele. The tension between them signals separate lives looming on the horizon.

That night, Agatha drives away from the house and is involved in a serious accident. The event marks a turning point as the couple's relationship fractures under pressure.

The next morning, police find Agatha's wrecked car and the press swarms the scene. A note left for her secretary fuels speculation that she may have attempted suicide.

Agatha disappears and arrives by train in Harrogate, checking into the Harrogate Hydropathic Hotel under the alias Theresa Neele. She plans a two-week stay to lay low and regroup.

In the hotel lounge, Evelyn Crawley notices Agatha's ripped stockings and muddy shoes and, perhaps unwittingly, Agatha makes a note to 'use' Crawley later. The encounter hints at the unraveling mystery surrounding Agatha's disappearance.

Agatha begins treatments at the Royal Baths while newspapers publish front-page stories about her disappearance. Archie remains away in Harrogate with Nancy for slimming, avoiding the search effort.

Stanton interviews Agatha's secretary, who reveals a coded message hidden in newspaper ads. The coded clues lead Stanton to the Harrogate hotel, deepening the mystery surrounding Agatha.

Stanton checks in at the Harrogate hotel under an alias and crosses paths with Agatha in the billiard room. They share an evening together; he makes a pass, which she declines, and he quietly keeps notes on her behavior.

Stanton begins following Agatha as she researches spa treatments and learns how the equipment works. She even reschedules Nancy's appointment by posing as a staff member, further hinting at a calculated motive behind the disappearance.

Agatha rigs the Bergonic chair after Nancy undresses for her appointment, triggering a dangerous malfunction. The moment turns deadly when a scream draws Stanton to the room, and he rescues Agatha with CPR.

The Christies claim Agatha suffered amnesia after the accident and remembers nothing. Later, Stanton confesses his love while handing her a copy of a story he wrote, confessing he cannot publish it.

Agatha tells Stanton she will divorce Archie, hinting at a possible future with him. They depart together by railway, and the epilogue reveals that Archie married Nancy two years later.