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.

As this personal love triangle forms, the "spectre of war" looms over Europe, threatening to dismantle the aristocratic world they inhabit. Parade's End episode 1 review - Den of Geek

Unlike the superficial Sylvia, Valentine matches Christopher’s intellect, sparking a deep connection that challenges his resolve to remain faithful to his unloving wife.

While playing golf with a government minister, Christopher rescues a young, fearless suffragette named Valentine Wannop (Adelaide Clemens) from the police after a protest.

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.