By the time any series reaches its sixth act, the joys and revelations within are only for the initiated and loyal. Anyone unfamiliar or indifferent with the previous episodes are left baffled and confused by the characters and the subtleties of their situations.

Even by that difficult standardD PRINCE!, HARRY POTTER AND THE HALF BLOOD PRINCE can only be truly enjoyed by the diehard fans of the series.

Picking up from the tumultuous events of ORDER OF THE PHOENIX, the film follows Harry, Hermione, and Ron through their sixth year at Hogwarts. Hormones are raging, and the three leads find themselves blindsided by the opposite sex. Their burgeoning desire for “snogging” distracts them from the Death Eaters swirling around the school, as well as the mysterious sulking of Draco Malfoy, who seems to be pressed with a heavy burden.

What miraculous choices Chris Columbus made in casting these three young actors so long ago! Rupert Grint really cuts loose in this installment, showing a keen sense of comic timing as Ron. Beautiful Emma Watson continues to deepen her interpretation of Hermione. But best of all is Daniel Radcliffe as Harry. He simply IS Harry Potter, and this is his best performance in the role. The three interact so well together, having had the unique opportunity to grow together like real friends on and off screen. Their chemistry together is formidable.

Beyond the three leads, the performances are spotty. Michael Gambon does solid work in the pivotal role of Dumbledore, managing to infuse some necessary humanity to the part. And, of course, Alan Rickman is awesome yet again as Snape, although he is never in any of these films as much as I’d like. Unfortunately, Helena Bonham Carter is allowed to painfully overact again as Bellatrix Lestrange, which now officially makes approximately fifty over-the-top performances in a row. Can someone please put a muzzle on her?

But it is Jim Broadbent’s performance as Professor Slughorn that really cements this film. The character is wonderfully imagined and written by J.K. Rowling and screenwriter Steve Kloves, but Broadbent layers in palpable regret and shame in between the laughs. It is a tasty and nuanced performance.

Director David Yates does a stylish and inventive job with the direction, and several scenes stand out nicely. He also handles the effects well, incorporating them just enough to emphasize the film, rather than overwhelm it. The film has a colder tone to it, and the cinematography pushes this with its chilly tableau of blues and grays. After AZKABAN, this might be my favorite direction and cinematography in the entire series.

Where the film goes wrong is with the story – there is none. Unlike the other films in the series, this movie has no plot whatsoever. The main function of this 2.5 hour film is to have fun with teenaged romance and set up the events of the final chapter. And frankly, that’s a bit much to ask of most audiences. The characters and situations are endearing, but a film should ultimately have a story to tell, and this movie is seriously lacking one.

That lack of story partially blunts yet another climactic showdown. In PHOENIX, the death of Sirius Black happened without even a whiff of drama or pathos. Here, another character’s death is treated similarly, entirely lacking in gravitas and suspense. Too much of this overlong movie feels lightweight, and it fails to build to a satisfying climax.

When I mentioned these nagging problems to my friends who have read the series, they became defensive. They loved this movie. I, on the other hand, have never read the books and have only seen each movie once. Perhaps I’m not as invested in these characters as the millions of fans of the series, thus tainting my view of this movie.

But I will say that I expect an engaging story from a film that asks almost three hours of my life. HALF BLOOD PRINCE has enjoyable moments, but it still feels like only half of a movie.