Two stars

With an intriguingly good title and two of England's finest actors on screen from start to finish, you'd be forgiven for thinking this is surely a must-see movie. But as Ian McKellen's character Roy says early in proceedings "there's the anticipation, followed by the letdown". Indeed. The Good Liar starts as a playful cat and mouse game of deception but rapidly loses its way, morphing into an unbelievable, convoluted and dark tale of revenge.

Roy (Ian McKellen) is a charming elderly con man, who flits from online dating with Betty McLeish (Helen Mirren) to swindling a couple of wannabe high-roller investors in an elaborate real estate fraud with Russian gangsters.

As he gets closer to Betty, we start to learn that his intentions are nothing more than another plan to get rich, with her a recently widowed victim with millions of dollars in savings. Faking a dodgy knee that makes climbing the stairs in his building difficult, Roy ends up staying at Betty's house where he meets her grandson Steven (Russel Tovey), who is researching German history at university.

Steven is less convinced of Roy's intentions, especially as Betty starts to plan the sharing of her savings with Roy and his partner in crime Vincent (Jim Carter) who poses as a friendly financial adviser. All the while, there's the sense that there's more to Betty: surely, she's not as naive and stupid as she behaves? Does she have a trick up her sleeve?

Well, despite her grandson's warnings, she seems incapable of seeing what Roy is really up to and, when the two of them head to Berlin for a holiday, Roy is confident that his wicked plans are finally closing in on her fortune.

With the players in Berlin, the plot takes a sudden and dramatic shift, secrets from the dark past emerging - not so much as to make sense of what's being going on - but to provide a highly unlikely backstory for the characters, told through a series of clunky flashbacks at the end of World War II. But it's the tonal shift that is most disorienting - what's been signalled as a mischievous con-game, with a jaunty score and knowing performances turns murky in the final act.

While Mirren and McKellen (who've never worked before on screen) are great to watch, you wish it wasn't in this. One moment they are asked to portray highly sophisticated schemers and the next sell their characters making dumb mistakes. At least it's an acting master class watching how they do it.

Director Bill Condon (Beauty and the Beast, Dreamgirls) and his regular team of creatives make sure there's a sophisticated elegance to the look and feel of the film, supported by the moody score from Carter Burwell. The screenplay is adapted by Jeffrey Hatcher and based on a novel of the same name by former British spy Nicholas Searle. Writer and director have worked together before, specifically on Mr. Holmes (2015) also with McKellen in the lead, and Hatcher's previous work in theatre explains much of the strategy to reveal information through conversation rather than cinematic action.

The entire third act of the film is a dialogue-heavy denouement with little opportunity for McKellen and Mirren to reveal the intense emotions that would have been in play for their characters. As a result, the ending is a deeply unsatisfying surprise. If you are a fan of these two great British actors, there may just be enough to warrant the ticket price, but the absurdity of the story is going to make that your challenge.