In 2007, I ended my review of Harry Potter and the Order of the Phoenix with the sentiment "I can hardly wait for school to start again." Two years later, with the release of Harry Potter and the Half-Blood Prince (Warner Bros.), I've come down with a bad case of senioritis. (A premature one, too. Now that the last book in the series, Harry Potter and the Deathly Hallows, has been split into two upcoming movies, graduation night is a long way off.) The Half-Blood Prince feels like the dreariest Harry Potter movie since The Chamber of Secrets in 2002—or maybe it's just that any film franchise designed to span an entire decade feels dreary by default.

At two hours and 33 minutes, this latest installment, directed by David Yates (who helmed the last film and who has bravely signed on for the duration of the franchise), gives the viewer ample downtime to reflect on the true wizardry the Potter movies have to offer. Like Michael Apted's 7Up films, which track a group of British schoolchildren from youth through middle age, the Potter series has allowed us to watch as three children, Daniel Radcliffe, Rupert Grint, and Emma Watson (playing, respectively: Harry; his best friend, Ron Weasley; and their almost-but-never-quite love interest Hermione Granger) grow from sweet-faced 11-year-olds to rangy young adults. That's an unusual privilege in the movies, where the process of maturation is usually represented by the replacement of younger actors with older ones who vaguely resemble them. Our simple sense of familiarity with these actors, and the goodwill they've built up over the course of the series, stands in for some of the character development that's missing from The Half-Blood Prince.

That goodwill comes in handy around the midpoint, when you begin to recognize this episode's chief flaw: the absence of a juicy villain. Ralph Fiennes' spectral Lord Voldemort appears only as a cloud formation looming over the proceedings; his evil designs on Harry are carried out mainly by the remarkably dull Draco Malfoy (Tom Felton), a fellow student who, having defected to the dark side, sulks around the halls of Hogwarts like a high-school Goth fresh from a spree at Hot Topic. Helena Bonham Carter pops up at intervals as the far scarier Bellatrix Lestrange, but her screen time is so limited that her character remains frustratingly vague. For example, why is she pregnant the first time we see her but not thereafter? Has she given birth to some awful creature that will haunt the final episodes?

Most of The Half-Blood Prince is unconcerned with questions about the nature and genesis of evil, and it's not until the last half-hour that we're treated to an old-school metaphysical showdown. This movie is just a long place-keeper episode, devoted to the shifting of allegiances both academic and romantic. As the new school year begins, Albus Dumbledore (Michael Gambon), the wizard headmaster of Hogwarts, gives his star student Harry a task: He's to get friendly with Horace Slughorn (Jim Broadbent), the newly rehired Potions teacher, who possesses some information about Voldemort's past that could help to defeat the dark lord once and for all. Meanwhile, Harry nurses a crush on Ginny Weasley (Bonnie Wright), the sister of his best friend, Ron, who is in turn pursued by the lovesick ninny Lavender Brown (Jessie Cave). Hermione's latent crush on Ron develops into full-blown pining as she watches him canoodle with Lavender, and there's a good deal of drama about who's going with whom to a holiday party at professor Slughorn's house. In short, too much of Harry Potter and the Half-Blood Prince resembles a lesser episode of Beverly Hills, 90210 with owls.

Despite the preponderance of (PG-rated) snogging, there are pleasures to be found along this movie's meandering path. As always, the production design (by Stuart Craig, who has been with the series since the beginning) is a labyrinthine marvel of detail. Hogwarts, presented in a desaturated palette that matches the series' increasingly gloomy mood, looks more enticingly explorable than ever. Alan Rickman, as the haughty professor Severus Snape, chews over each syllable as if mouthing some unspeakably distasteful goo. In a rather drab cliffhanger of an ending, Harry and his buddies gather on a parapet to swear a solemn oath that, as God is their witness, there will be two sequels. But in spite of the plodding tone of this antepenultimate chapter, there's something touching about the Harry Potter series' loyal love for its source material. * Whatever happens in the final faceoff between Harry and Voldemort, when the last movie comes out in the summer of 2011, a beautiful and intricate world will have come to an end.

Slate V: The critics on Harry Potter and other new movies

Correction, July 15, 2009: The sentence originally misidentified this movie as the ante-antepenultimate movie in the Harry Potter series. It is the antepenultimate movie. (Return to the corrected sentence.)