A nation divided with history hanging in the balance: Robert Icke’s new version of Frederich Schiller’s “Mary Stuart” reflects this runaway year. With a coin toss each night determining which roles actresses Juliet Stevenson and Lia Williams will play — one England’s Queen Elizabeth I, the other Scotland’s doomed Mary Stuart — it’s not so much the mirror image that strikes you as the contingency of it all. Everything might so easily have been otherwise and, in times of great churn, when history loses its head, the future is governed by chance — and by chancers.

So it is here. Schiller shows England’s queen crushing a Catholic uprising against her reign, quite literally cutting off its head by imprisoning, and eventually executing, Mary Queen of Scots, her opposite number and cousin. If her hand wavers over the death warrant, it’s for fear of setting a precedent for regicide. Sign away Mary’s life and she risks writing her own death warrant in turn.

These women are, in a very real way, two sides of the same coin. Not only are they one another’s sole equals, elevated above the populations they rule by their royalty, they are also both equally captive: one in defeat, the other in victory. As monarch, Elizabeth finds her hand forced — by her people’s will, by her jostling advisers, by logic and by faith, even by history itself. “The crown,” she says, “is just a prison cell with jewels.”

The coin toss makes that duality abundantly clear. Since either casting’s a possibility, each actress seems to contain the other somehow, and Williams and Stevenson are one another’s mirror images: their hair identically short, their blouses both brilliantly white, just as androgynous as each other.

They are, however, actors of very different timbre. Williams is elfin and quicksilver; Stevenson, sober and searching. When Williams plays Elizabeth, her manner suits a queen who knows sex is part of her arsenal, while Stevenson’s a penitant, almost puritan, prisoner as Mary. It’s just as easy to imagine the opposite: a stern, stoical monarch and a defiant, even dandyish, rebel.

However, as the coin spins, rumbling around in its brass bowl, the entirety of history seems briefly suspended. Either woman could emerge as the victor and, you realize, that’s how war works. The winner determines the future. They define the nation. Elizabeth persecutes England’s Catholics but, on another day, Mary might have purged it of Protestants. After a divisive referendum, a vote that might have gone either way, Britain’s future, its entire national identity, feels just as precarious once again.

This is basically Schiller as “Sliding Doors,” and it goes way beyond that one flip of the coin. Any single moment might send history spinning off elsewhere, and Icke stresses the sheer uncertainty of unfolding events. When the two monarchs meet — a meeting that “will decide everything” — emotions get the better of diplomacy. An assassination attempt misses its mark by mere millimeters: Williams emerges bloodstained, a bandage just shy of her jugular. Behind the two queens, loyalists jostle for influence, all these men trying to grab the steering wheel for their own ends and ideals. Vincent Franklin’s technocrat Burley outmaneuvers John Light’s alpha Leicester who had, himself, seen off Rudi Dharmalingham’s young radical Mortimer. One slip and they’re out — a footnote in history — but all of them are improvising: opportunists on the hoof.

That’s the terrifying thing about this “Mary Stuart”: No-one’s in control, but everything’s at stake — and don’t we know how that feels. Icke plays it at full pelt, with the utmost of urgency, fraught as hell. It springs onto the stage and shouts itself hoarse, and what’s lost in narrative clarity is gained ten times over in nerve-shredding thrills.

Like all good thriller writers, Schiller supplies a great twist, but suspense gives way to horror. Victors tend to wipe out opposition and, as Elizabeth ends deified — the actress transformed into the icon we know — Mary ends up entirely destroyed. History is a zero-sum game. The winner takes all.

London Theater Review: ‘Mary Stuart’ at the Almeida Theater

Almeida Theatre, London; 325 seats; £38 ($47) top. Opened, December 15, 2016; reviewed Dec 14. Running time: <strong>3 HOURS, 15 MIN.</strong>

  • Production: An Almeida Theatre production of a play in two acts by Frederich Schiller
  • Crew: Adapted and directed by Robert Icke; design, Hildegard Bechtler; lighting, Jackie Shemesh; composition, Laura Marling;
sound, Paul Arditti; video, Tim Reid.
  • Cast: Alexander Cobb, Rudi Dharmalingam, Vincent Franklin, David Jonsson, John Light, Carmen Munroe, Eileen Nicholas, Daniel Rabin, Sule Rimi, Juliet Stevenson, Alan Williams, Lia Williams.