Those immersed in the Harry Potter universe need little help figuring out what happens in the latest, “Harry Potter and the Half-Blood Prince.” But for those more familiar with the movies than the books, here's a helpful summary: Hordes of what the stories refer to as muggles — unmagical civilians — are bewitched and lured to their local cinema once more, where they're boxed about the head and ears with hoary gobbledygook. The spell is so strong the poor devils emerge some two and a half hours later ranting about how much they loved the experience.
As for an assessment, it's every muggle for himself. I can only tell you what I witnessed, not what it means.
In the new movie the evil forces of Voldemort are still gathering and plotting, while benevolent Professor Dumbledore (Michael Gambon) and Harry (Daniel Radcliffe) try to stop them. Meanwhile, an encyclopedia of memories that Dumbledore magically keeps on file have somehow been edited when nobody was looking.
In the opening scenes Dumbledore whisks Harry to the home of Horace Slughorn (Jim Broadbent), a former professor at Hogwarts School of Witchcraft and Wizardry, whom they hope to coax out of retirement.
Their method of travel looks like a bad acid trip on fast forward, or like what happens when a computer animator accidentally presses the wrong key. Dumbledore wants Harry to meet the old guy so Harry can butter him up later at Hogwarts and retrieve bits of mystery only Slughorn possesses — parts of a former rogue student's memories that have gone missing from the archive.
What follows is the usual cat and mouse between Harry and the forces back at school trying to stop him, which may or may not include the sinister-looking but Dumbledore-trusted professor Snape (Alan Rickman). Harry listens in on various doings, gathers clues, searches his soul, mixes it up with fellow students and gives romantic advice, all so that, in the end, he can — wait, just ask Slughorn? That's it?
What's that, you say? Why didn't Dumbledore just ask Professor Slughorn in the first place?
That would end the movie at minute 13. In order to shoot past the two-hour mark, magic at Hogwarts can work only when it's convenient for the plot. Simple, nonmagical problem-solving also would leave no reason for Harry to find an old potion-making book signed by the mysterious Half-Blood Prince, who was kind enough to fill it with marginalia that happens to help Harry through the current episode.
And if Harry didn't find the book, he wouldn't win the class prize, a luck potion which, when imbibed, helps him ... run into Slughorn, on school property of all places.
OK, so it really doesn't turn out to be much of a luck potion.
Better realized is the bowl into which Dumbledore pours those memories he keeps. Midway through it becomes necessary for Harry to dunk his head in and, Pow!, he's in the middle of a broken memory, or what you or I would call a rather run-of-the-mill flashback. A couple of those memory experiences, chapters in the life of young Voldemort, were so long I thought poor Harry had surely drowned. Alas, he was fine, and the movie dragged inexorably on.
Likely, it's enjoyable to contemplate luck potions and Horcruxes chapter by chapter in the books, but the movies struggle to keep them out of the plot's way, allowing them to clutter what's really important and why. If you have questions — why all the memory-collecting in the first place? — it's best if you've come prepared with your own notes. “Harry Potter and the Half-Blood Prince,” like the kids at Hogwarts, is too busy getting sidetracked by concoctions and creatures to be proper help.
The magic shop in the series is a fine analogy. This funhouse of charmed apparatuses seems on hand for the same reason the movies get made: It's a place to spend a couple of hours ogling neat magic stuff, with the concession that there's simply too much of it to bother with reason and explanation.
“I'll let you in on something others have only guessed at,” Harry says, a little more than halfway through the movie, trying to pry the memory out of Professor Slughorn. The faithful might inch ever closer from their seats to hear this revelation, but the information turns out to be obvious (and unoriginal) news to anyone outside Hogwarts. I didn't especially want to hear it. The more one learns at this place of magic, the less sense it all makes. (PG) 153 min. HHIII S