Grade: 2.0/5.0

When a film is labeled a “star vehicle,” it’s inferred that ensuring the quality of the film itself is negligible compared to simply handing the stars a stage. And that’s not an unfair inference; it can be thrilling to just watch your favorite stars chew scenery without the interjection of some maudlin attempt at cinematic grandeur. But that’s the key: A star vehicle cannot get in the way of the stars.

And it’s because of this failure that “The Good Liar” never quite snaps together. As a star vehicle for Helen Mirren and Ian McKellen, “The Good Liar” treats the audience to a gluttonous feast of classically trained British acting. But too often the performances are interrupted by a script that is at once numbingly beige and needlessly inane.

And that’s a shame, because from the film’s fantastic opening, “The Good Liar” appears poised to put on a fireworks display. Sharp cuts in the opening credits bounce back and forth between the Golden Age lead duo Betty (Helen Mirren) and Roy (Ian McKellen) as they embark on a less-than-honest online courtship. Paced to the jabs of piano keys and flurries of strings from a white-knuckled score by Carter Burwell, this scene ingeniously helps frame their initial date with a sizzling taste of mistrust. And the date itself is layered with the same magnetic tension as when Pacino first met De Niro for coffee in “Heat” — which seems appropriate, considering “The Good Liar” is shockingly the first time Mirren and McKellen have appeared together on screen. This meeting is as enthralling as you’d expect, showcasing the duo’s ability to harmonize suspicion with instant romantic chemistry.

It’s no surprise, as we soon learn, that Roy’s hobbled old-man act is merely a front for a savage, calculating con man. But while the elements of a biting and twisty thriller exist as Roy develops his financial con on Betty — a historical detour in the second act especially digs an intriguing possibility of depth — it’s nominally in the more intimate moments of Roy and Betty’s relationship that “The Good Liar” shines. It’s in these scenes that we get to witness Mirren and McKellen unabridged.

Recalling their Shakespearean acting backgrounds, the two actors play a finely tuned orchestra of loneliness, deceit and ultimately passion to become a genuinely affecting couple. Out of the two, it’s McKellen who mostly steals the show: Every tightening wrinkle on his worn face and delicate flinch of the eyes is trumpeted by his guttural groans, and his performance manages to bleed both sympathy and the vile contempt of his 2008 rendition of “King Lear” in equal measure. But if McKellen shines the most, it’s only because he’s given more to work with; when allowed, Mirren likewise combines a deeply caring persona with touches of the edge she showed as Prospera in the 2010 film “The Tempest.” 

Yet while “The Good Liar” intermittently shines as a star vehicle, its uninspired screenplay (written by Jeffrey Hatcher and based off a Nicholas Searle novel) drains the film of its stars’ absorbing promise; the problem isn’t that “The Good Liar” fails to live up to the Shakespeare Mirren and McKellen have worked with in the past — it never needed to. Rather, the fatal flaw lies in the script’s blandly uninteresting design. As a cat-and-mouse thriller, it lacks the requisite twists and elemental danger to let its stars loose. But while the resulting simplistic framework makes “The Good Liar” structurally predictable, the concrete material of its primary twist is so preposterously out of left field that it also manages to overshadow its stars’ performances.

Even if one were to give the film the benefit of the doubt — maybe it was ambitiously attempting to reach beyond standard B-movie schlock — it fails as well. When the film attempts to assume the role of a character study to capture deeper themes of lifelong justice and regret, it lacks the contemplative grief of better Silent Generation-focused movies such as last year’s “The Old Man and the Gun”.

The result is unsurprisingly breathtaking performances, turned sour by a film that’s so difficult to swallow.