The story of , Season 1 Episode 1, begins in the final days of the Edwardian era with Christopher Tietjens (Benedict Cumberbatch), a brilliant but rigidly principled government statistician.
Unlike the superficial Sylvia, Valentine matches Christopher’s intellect, sparking a deep connection that challenges his resolve to remain faithful to his unloving wife.
Following a brief, passionate encounter on a train, Christopher enters into a hasty marriage with the beautiful but cruel socialite (Rebecca Hall). Sylvia is already pregnant, and though the child's true father is likely her previous lover, Christopher’s strong moral code compels him to "resume the yoke" and provide her with security and a name. Key events in the first episode include:
While playing golf with a government minister, Christopher rescues a young, fearless suffragette named Valentine Wannop (Adelaide Clemens) from the police after a protest.
Years into their marriage, Sylvia remains unfaithful and disdainful of Christopher’s "stiff upper lip" morality, eventually running off to France with a new admirer.