Darker, thrilling, mature and funny, the third film in the Harry Potter series brings with it a marked shift from the way the earlier two Potter movies have been made and viewed.

Harry Potter And The Prisoner Of Azkaban makes for an enjoyable movie-going experience, especially after its somewhat disappointing predecessor, Harry Potter And The Chamber Of Secrets.

Prisoner of Azkaban sees the young boy wizard Daniel Radcliffe) about to return to his third year at the Hogwarts School of Witchcraft and Wizardry. Harry has just stepped into the first year of his teens and already the teenage angst and temper are beginning to show. An example of this is seen at the beginning of the film when Harry uses magic in the house of his Muggle guardians after he is unable to control his temper.

Disgusted at his uncle and aunt, Harry storms out of the house. Sitting alone on the pavement outside, he is picked up by a wacky Knight bus, which zooms around the streets of London in hyper-drive. The bus drops him off at the Leaky Cauldron where he meets up with his best pals, Ron Weasley (Rupert Grint) and Hermione Granger (Emma Watson). Here, Ron's dad tells Harry that Sirius Black (Gary Oldman), a fearsome murderer, wanted among other things, for the murder of Harry's parents, has escaped from the confines of Azkaban prison with a single intention in mind -- to kill Harry Potter. It is with this chilling knowledge that Harry makes his way back to Hogwarts.

The movie follows Harry's most emotionally turbulent year yet at the school. It is a roller-coaster ride as he discovers unexpected things about his life in trying to piece together his past with the help of Professor Lupin (David Thewlis). Professor Lupin helps Harry unravel the mystery behind the enigma named Sirius Black.

During the course of the movie, it is difficult not to realise that this no longer is a purely children's movie. The Harry Potter series is getting darker all the time and Harry Potter and the Prisoner of Azkaban is the darkest of the three movies. There is an apt, though clichéd, use of dark clouds and rain to convey the mood throughout the movie.

Director Alfonso Cuarón takes over the reins from Chris Columbus and interprets the third Harry Potter book as a coming of age story for our bespectacled boy wizard. In doing so, he rightfully focuses on Harry while relegating some of the other characters into the background. Professor Dumbledore (Michael Gambon who takes over from the late Richard Harris), Professor McGonagall (Maggie Smith), Professor Snape (Alan Rickman) are victims as they are left with just a few scenes in this long movie (running time: 136 minutes). On the other hand, the characters of Hermione Granger and a wisecracking Ron Weasley are treated on par with Harry. The movie also comes alive with the addition of two excellent actors, David Thewlis and Gary Oldman, both of whom add muscle to an already impressive cast of characters which, once again, includes Robbie Coltrane as the gentle giant, Rubeus Hagrid.

One of the movie's biggest strengths is the impressive use of special effects. While the effects themselves aren't groundbreaking in terms of the technology or magnitude, their use is intelligent. They blend seamlessly with the spectacular sets and locations in the movie. The part-horse, part-eagle creature, the Hippogriff, looks magnificent, graceful and life-like and its flight, with Harry riding it, is one of the most memorable sequences in the movie. The brief Quidditch sequence is also breathtaking and leaves one asking for more.

Any review of Prisoner of Azkaban would be incomplete without mentioning the Dementors, those vicious, soul-sucking guards from Azkaban who feed off their victims' happiness leaving them with only sad memories. The portrayal of these creatures seems to be influenced by the Ring-wraiths from the Lord of the Rings movies. But they look scary all the same.

Some of the best scenes in the movie are those involving Harry and Professor Lupin. Their interaction goes a long way towards Harry understanding his troubled past. The subtle, yet definite, hints of chemistry between Ron and Hermione are cute and bring a smile to the lips. So do Professor Dumbledore's attempts to help his favourite student.

The performances are up to the mark. The actors, who must now be supremely comfortable and confident in their respective roles, brilliantly portray all the lead characters. Michael Gambon fits perfectly into the character of Professor Dumbledore while Gary Oldman portrays Sirius Black with consummate ease.

The cinematography by Michael Seresin is brilliant. John Williams provides an excellent musical score. The casting by Jina Jay is a triumph. Editing (Steven Weisberg) seems to be a weak point with a patchy opening which means that the movie settles into a smooth flow about 30 minutes later than it should have done. Moreover, the movie seems to be longer than it should have been. As a result, the ending seems to be a bit rushed. Alfonso Cuarón, whose last movie was the coming-of-age Y Tu Mamá También, goes to great lengths to ensure that the film's focus remains the young Harry Potter.

One grouse Potter fans will have is the movie's failure to stick to the book's plot. There are a few instances where the movie isn't completely faithful to the book and Potter fans will notice them without any difficulty.

But then, books and movies are completely distinct media and what works well in one may not work as well in the other. Given this, Cuarón has managed to come up with an entertaining and meaningful movie that does not treat young Harry Potter as a child and yet appeals to the children of all ages with its intelligent mix of thrills, fantasy and some great acting.

Sameer Gharat is a software engineer in the UK.