“HARRY POTTER AND THE HALF-BLOOD PRINCE”

“Exactly who is the Half-Blood Prince,” you might ask. But the answer doesn’t come until nearly the end of this 153-minute film journey illuminating the adventures described in the first half of this sixth novel by the transcendent British author J.K. Rowling. The seductive power of the fantasy world she creates with words has become both a strength and weakness in the cinema world.

Fans of the Harry Potter books don’t really need to see the films. And film fans who don’t read the books never quite understand what’s spiraling across the screen. We do appreciate the fidelity all the filmmakers have applied in recreating the atmosphere of Rowling’s books. It is always enchanting and foreboding, much like the real world of every young person.

The bad news for movie buffs is that this time out, as adolescence wraps its taut fingers around the hearts of Harry, Ron and Hermione, the dark plot that will charge Harry’s entire adult life becomes even more inscrutable. On the surface, it seems like solid Harry (Daniel Radcliffe) is leading a student revolt against the Dark Forces led by devilishly sinister Lord Voldemort (who doesn’t appear in this picture).

But as the battle between light and darkness begins to take on more mythic proportions, this film directed by David Yates becomes more timelessly Gothic spiraling into a black hole of foreboding shadows. We remember there used to be talk that Harry would grow up to be the Chosen One, some sort of wizard-like Jesus who would create a golden world of kindness for everyone.

So we begin to wonder, will the benevolent Professor Dumbledore (Michael Gambon) save Harry by uncovering some fatal flaw in the student personality of Voldemort when he was a brilliant pupil at the Hogwarts School of Witchcraft and Wizardry? Guest professor Horace Slughorn (Jim Broadbent) is called out of retirement to lend Dumbledore a hand, comparing their memories of this twisted boy. Searching for the clue that will unravel his past.

Adding his own twist is Professor Snape (Alan Rickman), who could be a double agent pretending to be evil just so he can learn the Dark Lord’s secrets. Or maybe Snape is only pretending to be good because, at heart, he is evil.

Fans of both the books and the films are titillated by the prospects of magical hormones stirring in Harry, Ron (Rupert Grint) and Hermione (Emma Watson). So far, we only get a teasing taste. Radcliffe may be appearing nude on London stages on his off time, but on the screen as Harry Potter the actor is still mostly, convincingly innocent.

Ron is becoming a quidditch jock and a dufus, which can be entertaining. But we have to wonder what the demure beauty Hermione could possibly see in Ron as mating material. Rowling’s cinema translators have yet to write the big scene that defines Hermione’s personality.

So far, Harry is growing up to be a James Bond type of gentleman’s rogue. Ron will become the sort who will make a killing in the construction business. Hermione, though less defined, could achieve Princess Diana’s beloved greatness with the people. We must all hope Watson the person doesn’t succumb to the temptations of, say, Britney Spears.

So here’s the thing. “Harry Potter and the Half-Blood Prince” has some dazzling digital special effects, some moments of sweet love and some heavy metal conflicts. For less motivated Potterheads, it will also drag in the middle. But we can all go in knowing the greatest Harry Potter movie has yet to be made.