A sullen Minister of Magic Rufus Scrimgeour (Bill Nighy) sets the mood for this seventh and penultimate instalment of Harry Potter. "These are dark times, there's no denying," he intones gravely, pointing out the grim state of affairs facing the nation- murders, disappearances and raids- but reassuring the public, as any politician would, that his Ministry has it all under control. Of course, he is only bluffing, and it doesn't take long before the palpable sense of doom and despair convinces you otherwise.

Welcome back to the magical world of Harry Potter, one that began with wonder and joy, but has since become shrouded in death and darkness. Still visibly distraught from the death of his mentor Professor Albus Dumbledore, Harry is now tasked to continue with the mission of the late Dumbledore- to find and destroy the remaining Horcruxes (accursed objects containing fragments of Voldemort's soul). It doesn't get any easier, since Voldemort is nearing the height of his powers, and his bidders have infiltrated the bureaucracy to paint Harry as a wanted criminal.

There are fewer and fewer allies around- even those within the Order of the Phoenix may have since betrayed their ranks- and the first half hour quickly establishes the danger and urgency of the situation at hand. Members of the Order, including Mad-Eye Moody (Brendan Gleeson) and Hagrid (Robbie Coltrane), attempt to escort Harry to safety- but even that mission is met with an attack from the Death Eaters, culminating in a dizzyingly exciting high-speed flying-bike chase that shouldn't disappoint fans looking for some action sorely missed in the last movie.

Indeed, naysayers who think David Yates doesn't know how to stage thrilling action sequences should think again, as he demonstrates amply that he is just as capable when it comes to staging them. He also displays an uncanny knack for milking suspense out of scenes- in particular, Harry, Hermoine and Ron's daring raid on the Ministry of Magic and their subsequent visit to Godric's Hollow, Harry's birthplace and home to Bathilda Bagshot, a magician and dear friend to Dumbledore. These brim with nail-biting tension, and Yates plays them out nicely to set your pulse racing at the end.

The crux of this film however lies in the relationships between Harry, Hermoine and Ron as they set off in the middle of the film across the bleak English countryside on their quest to discover the means to destroy the Horcruxes. On the run from Voldemort, the trio find the immensity of their journey taking a toll on them. Harry and Ron's friendship begins to fray as Ron grows suspect of Hermoine's affections for Harry. Meanwhile, Harry can barely conceal his frustration with getting no headway and starts losing his temper at Ron.

Infused with a profound sense of isolation and loss, this middle stretch in the film may be tedious for some impatient viewers, but fans will be rewarded with probably the richest depiction of the relationships between the characters since the first two movies. One scene where Harry and Hermoine suddenly decide to dance together to the tune of Nick Cave's The Children playing on the radio is lyrical in its depiction of their desperate attempt to find levity in a world that affords none. Yes, their friendship strong and deep since the beginning will be tested, and Yates delivers an emotional payoff towards the end of the film that is truly poignant.

Thanks to the decision to split the final book into two films, Yates doesn't hurry through these scenes. Instead, he allows the audience to experience the frustration, jealousy and uncertainty of his characters, and allows for Radcliffe, Watson and Grint to display some fine acting with the minimalest distraction from any visual effects. The additional time also turns out to be a blessing for fans and audiences, allowing them the opportunity to see their favourite supporting characters back on screen- most prominently of course Dobby the elf who returns to give the movie a touching finale.

Amidst the gloom, screenwriter Steve Kloves again provides for rare welcome moments of levity. Harry's escort mission is aided by magical decoys of Harry, one of them wearing a bra. To get to the Ministry of Magic, one needs to flush oneself down a toilet bowl. These occasional sparks of humour enliven a film that is otherwise ominous and menacing. Kloves however fumbles slightly with the lengthy expository, and those who have not read the book will find themselves struggling to catch up with the significance of certain characters (e.g. Sirius' brother, Regulus Arcturus Black) and certain events (e.g. Bathilda turning into a slithering serpent).

Still Kloves never had an enviable task to begin with, and Yates- at his most confident here- guides the proceedings along admirably, unfolding them briskly at the start, then settling in for a deliberately measured pace and finally picking up speed for as much as a climax as this first- parter can have. His assuredness also shows in his artistic choices, especially a wayang-kulit-like animated sequence telling the story of the Deathly Hallows.

Though we know better than to expect the grand showdown between Harry and Voldemort by the end of the film, there is still a distinct sense that what we have seen so far is only a build-up for something bigger and far more astounding. But even as a prelude, this seventh film is notable in its own right, a tense and thrilling experience darker, scarier and more mature than any of its predecessors