Christopher Nolan gave himself a simple manifesto when beginning work on The Dark Knight Rises, the latest - and final - instalment in his Batman series.
'I think the challenge with a sequel is to give the audience a reason to come back to Gotham,' the director and screenwriter says, referring to the fictional city in which the stories are set.
The hotly anticipated film has a vast and loyal audience: The Dark Knight, Nolan's second stab at the Batman franchise in 2008, brought in more than US$1 billion in worldwide box office take, a response that the filmmaker to this day describes as 'a phenomenon'. Audiences turned up in droves to see the Caped Crusader take on Heath Ledger's Joker, a startling performance that won the latter a posthumous best supporting actor Oscar.
Still, everyone involved with the project - from Nolan and his co-writing brother, Jonathan, to star Christian Bale and newcomers to the series Anne Hathaway and Joseph Gordon-Levitt, knows the stakes are high: the special effects have to be more astounding, the chases more thrilling, the story more compelling - and the arch-villain even more menacing.
In determining against whom to pit Batman in this ultimate tale, the storytellers settled on the character Bane (played by English actor Tom Hardy) who is perhaps the most terrifying of them all: a muscular mask-wearing revolutionary who lives underground, breaks his victims' necks with a flick of the wrist, and seems almost impossible to kill.
Finding a way to wrap up the franchise satisfactorily, while capturing some of the gargantuan success of the previous film, has not been easy even for Nolan, one of the industry's most respected filmmakers. But he says he remained true to what he set out to do with Batman Begins in 2005 - that he wanted there to be a consistent story throughout.
'We didn't want to do another episode,' he says. All of the elements and plot points, he adds, 'had to mean something'.
Jonathan Nolan describes the process as having 'to keep the plates spinning. As sad as I am to end on this final chapter, I am excited to tell a complete story', he says.
When The Dark Knight Rises opens, it is eight years after Batman has taken responsibility for the death of Harvey 'Two-Face' Dent, played in the last film by Aaron Eckhart. As far as Gotham is concerned, Batman is no more; and his alter ego, Bruce Wayne, billionaire industrialist and philanthropist, is in self-enforced isolation, a recluse with a limp.
As is wont to happen, however, forces conspire to bring Batman out of retirement, much to the chagrin of his loyal butler and friend, Alfred, played again by Michael Caine. But Batman has more important things to worry about than upsetting the help: tortured madman Bane is rampaging through the city, causing all sorts of devastation.
The character of Catwoman - played by Michelle Pfeiffer in 1992's Batman Returns - is reintroduced, with Hathaway stepping into an unforgiving catsuit and vertiginous heels, and a plot involving clean energy and civil revolution.
Some of the fight sequences are, inevitably, spectacular - as are the gadgets and gizmos Batman gets to play with.
Because it is the last of the series, it is hard to predict - while watching - what might happen, which is why Bane is such an interesting choice as the villain.
'In 70 years [since the character was created], Bane is the only one to have put a dent in Batman,' says Jonathan Nolan. 'The Joker was an anarchist, but Bane has a plan and it's terrifying, and that's very apt for the end of the story.'
His brother says they chose Bane because 'we wanted a very different character'.
While there are momentary flashbacks to some of the other villains Batman has fought, Ledger's Joker is not among them. 'We made the decision not to reference Heath,' Christopher Nolan says. 'He suffered a terrible tragedy, and it felt wrong to reference that as a plot point.'
Gordon-Levitt, who plays John Blake, an earnest Gotham City policeman, is another interesting casting choice: he worked with Nolan on Inception (2010), but made his mark in smaller films such as 500 Days of Summer (2009) and last year's 50/50).
But starring in a big Batman movie has been a life- and career-changing experience, the actor says. 'I remember seeing The Dark Knight when it came out, twice. I loved it so much, and I had no inkling that I was ever going to be involved,' Gordon-Levitt says. 'Two years later, I did Inception. I have been a fan of Christopher Nolan ever since [2000's] Memento.'
In The Dark Knight Rises, Christopher Nolan hews close to the source material, but has made the film contemporary and filled with human emotions - even if it is a superhero movie.
'I enjoy working in this unnatural medium, this heightened reality,' he says. 'It frees me up to try to make a more universal experience for the audience. That is part of the enjoyment of this film.'
Nolan shot the film on one of four Imax cameras in the world, giving audiences another option to experience his film. 'I've simply never seen anything that matches that resolution and its immense power,' he says of the format. 'In telling a three-part story, we wanted it to be visually consistent. We are not reinventing something, but building towards a climax.'
Emma Thomas, one of the film's producers and Nolan's wife, says that offering an Imax component provides an additional draw to audiences. 'It's a real reason to get people out of their homes and into the movie theatre. It's really got to be something special that gets people out these days.'
That the previous film pulled in more than US$1 billion at the box office to become one of the highest-grossing films of all time adds a bit of pressure on the filmmakers - but Nolan says he makes an effort to try not to think about any of that. 'When you set out to make a film you feel a lot of pressure,' he says. 'But it would be crazy to chase the kind of success [of the preceding film]. My responsibility is to try to make a film for the studio where they make their money back.'
Bale, whose brooding, complex portrayal of the superhero has been critical to the franchise's success, says bidding goodbye to Batman is bittersweet. 'I wasn't sure that Chris was even going to make a third one,' he says. 'It's meant a great deal in my life. But it's time to say goodbye.'
The Dark Knight Rises opens on Thursday