Dame Judi Dench gives a commanding performance as always, but this time-hopping spy thriller suffers from tepid, made-for-BBC delivery.

At the start of Red Joan, a brief caption informs viewers that this movie is inspired by true events. To be more accurate, it is an adaptation of a book that told a fictional story inspired by true events. So you true story junkies out there, take note.

For me, though, I felt a bit of zip at how far removed from a “true story” the movie actually stood. None of that pesky reality getting in the way of telling a ripping yarn and all that.

Sadly, I was mistaken.

To backtrack a bit, Red Joan tells the story of Joan Stanley (Dame Judi Dench), a pensioner who finds herself arrested after the death of a high-ranking official reveals him to be a spy and suggests she was as well. As the British government interrogates her about her actions before, during, and after World War II, the film takes us back in time to show us exactly what young Joan (Sophie Cookson) had been up to at the time.

An intelligent college student underestimated by many of the men around her, she is often able to move free of detection. Her intelligence sees her graduating from university with a degree in physics and an excellent reputation making her a strong candidate for Britain’s version of the Manhattan Project. Her gender and all the biases that come with it make her an attractive recruit for the KGB who covet the nuclear secrets their WWII allies claim to be sharing with them but have long since stopped.

A sound enough premise to be sure. The far-removed true story of Melita Norwood under her 40 years of spying—as opposed to Joan’s mere handful—holds the promise of being quit a tense thriller. Red Joan, alas, shows little interest in being thrilling.

Acting wise, everyone delivers good performances. Cookson, in particular, keeps herself on a low boil showing us both how she could be passionate to betray those around her and controlled enough that they would never suspect a thing. That sense of control, however, extends to the rest of the film, flattening its intensity.

Red Joan, alas, shows little interest in being thrilling.

Spying can be dangerous business, but the movie never lets you feel that. Even as it literally tells us that the price of treason in Britain is hanging or shows us what happens to one of Joan’s lovers who is suspected of not being loyal to the cause, a viewer’s pace never quickens. The story structure hardly helps things. Every time we cut from the past to the present, what little tension has been built, escapes like air out a pierced tire.

And those scenes in the present? Mostly Dench looking uncomfortable and her interrogators questioning her in raised but never emotional voices. Only her son Nick (Ben Miles) brings any kind of emotional heat to the present-day scenes, making his final choice all the more confusing and ill-conceived.

The story of a principled woman in the late 30’s committing treason to save the world from further wars has such potential for power that one can understand why all the players were attracted to it. Alas, in the end, Red Joan misuses their talents on a tepid delivery that sidesteps passion when it could give us insight and dodges intensity when it could draw us in.