Alfred Hitchcock tells a famous story to clarify the difference between suspense and surprise that’s particularly pertinent to The Good Liar. You might have read it before; it goes like this:

We are now having a very innocent little chat. Let’s suppose that there is a bomb underneath this table between us. Nothing happens, and then all of a sudden, “Boom!” There is an explosion. The public is surprised, but prior to this surprise, it has seen an absolutely ordinary scene, of no special consequence. Now, let us take a suspense situation. The bomb is underneath the table and the public knows it, probably because they have seen the anarchist place it there. The public is aware the bomb is going to explode at one o’clock and there is a clock in the decor. The public can see that it is a quarter to one. In these conditions, the same innocuous conversation becomes fascinating because the public is participating in the scene. The audience is longing to warn the characters on the screen: “You shouldn’t be talking about such trivial matters. There is a bomb beneath you and it is about to explode!”

In the first case we have given the public fifteen seconds of surprise at the moment of the explosion. In the second we have provided them with fifteen minutes of suspense. The conclusion is that whenever possible the public must be informed. Except when the surprise is a twist, that is, when the unexpected ending is, in itself, the highlight of the story.

The Good Liar is an example of the latter kind of story: one that prioritises surprises over suspense. It should not surprise you to learn that Bill Condon’s film is adapted from a novel; there’s an undeniable ecosystem in contemporary Hollywood for turning trashy airport books into thrillers. Having not read it, I admittedly can’t speak to the quality of Nicholas Searle’s 2016 novel; but if Condon’s adaptation is at all faithful, ‘trashy’ is certainly the operative word.

But trashy doesn’t necessarily mean bad. Take Gone Girl – an obvious influence on The Good Liar – which elevated the themes of Gillian Flynn’s novel while wryly recognising the story’s inherent ridiculousness. That’s a rare example of this subgenre that manages to balance sophistication with silliness, and Condon takes a similar approach to The Good Liar …if not quite as successfully as Fincher.

To Condon’s credit, he knows how to construct a gripping thriller sequence. A good example is an early scam enacted by Roy Courtnay (Ian McKellen). Though we’re first introduced to him in the context of an internet-facilitated date between Roy and widow Betty McLeish (Helen Mirren), the screenplay wastes little time establishing that Roy is more than a sweet, doddery old man. He traipses through a strip club for an anonymous meeting, where he plans an investment scam with three men.

They’re scheming to divest Russian investors of hundreds of thousands of pounds through a phony real estate investment; after adding their own contributions to a joint account, the Russians’ money will be siphoned away. We’re witness to a tense boardroom meeting, our con artists nervously waiting for the transfer to proceed successfully. But then – shock! – it turns out one of the Russians is wearing a wire, and the cops are on the way! We subsequently learn that this is just one step in a larger scam; the Russians are actors, the cops aren’t cops, and the actual con was on two of the anonymous investors. It’s a cleverly constructed scene, in that it contains both the “suspense” Hitchcock was prioritising – we’re nervous about the scam going ahead as planned – with the sting of a “surprise” waiting at the end to recontextualise events.

It’s clear that Condon is trying to mirror this structure across the entire film. The ongoing suspense comes from the dynamic between McKellen and Mirren’s characters. Will he be able to con his way into her heart? Or will she – and her increasingly sceptical grandson, Steven (Russell Tovey) – cotton on to Roy’s ulterior motives in time? Of course, there’s more to it than that, including an historical scandal involving wartime Germany – but I daren’t divulge the details. The surprise is best kept as such.

Unfortunately, despite a pair of talented actors, Condon isn’t able to thread the needle as successfully across the film proper. If I were to diagnose the issue, I’d single out two factors.

First, the tension underlying Roy and Betty’s relationship isn’t substantial enough to shoulder a feature runtime. It holds your interest for a while, but there aren’t enough complicating factors in the plotting or characterisation to maintain audience interest. I think Condon misses a trick here – the precise trick Hitchcock outlaid all those years before. There’s a natural spot for a rug pull around the midpoint of the film, but Jeffrey Hatcher’s screenplay withholds all the information until the obligatory big reveal at the climax. We can only suspect there’s a bomb, and we can’t precisely know what it looks like; if only we’d been allowed to peek under the table a little earlier, we would’ve been more engaged – and more prepared to forgive the characters’ increasingly implausible actions.

Secondly, the film’s attempts to split the difference between sophistication and silliness are sadly misjudged. As the plotting becomes more ludicrous, the foreshadowing ramps up; if you can’t spot at least the shape of the twist coming, you’re not paying much attention. This foreshadowing is inherently silly (I was reminded of A Simple Favour’s broad, pseudo-parodic take on the genre more than once), which is in of itself totally fine. Where it struggles is when it’s placed alongside a story of Nazis and sexual assault, which Condon frames very seriously. These elements don’t have to be immiscible, but in The Good Liar they are – and the film suffers for it.

As such, despite The Good Liar’s numerous pleasures – Condon and cinematographer Tobias A. Schliesser’s handsome compositions, Mirren and McKellen’s ever-reliable work – I can’t really recommend it. That said, if you’re a fan of trashy thrillers and farfetched twists overlaid with a veneer of sophistication, you could do a lot worse.