'Harry Potter and the Deathly Hallows, Part 1'

Courtesy of Warner Bros. Pictures

Extras on the new Blu-ray allow the viewer to figure out just what the heck is going on with Harry and the gang.

If any movie ever cried out for a commentary feature, it's the second-to-last Harry Potter adventure, about the Hogwarts dropouts' quest to make Lord Voldemort less immortal by giving him a sharp stab in the Horcrux. After six movies, there's a bewildering profusion of Snatchers, Death Eaters and backstory to know (like, what's a Horcrux?). So it would be great to have the equivalent of Harry's Marauder's Map, a magical device to show where everybody is at all times and the secret passages connecting everything.

And wouldn't it be cool if the commentary were less ordinary and distracting than the usual DVD voiceover track or making-of minidoc? Magically anticipating our need to figure out just what the heck is going on in Deathly Hallows, Part 1, Warner wizards made a spellbinding feature for Blu-ray Disc titled Maximum Movie Mode. It lets you watch the movie straight through, but every few minutes the screen shrinks to the size of a weatherman's graphic, and somebody — usually jaunty Jason Isaacs, who plays bad guy Lucius Malfoy — says, "Just freeze it there," and explains the significance of, say, the Deluminator you've just seen. "Where have you seen it before? In the first scene of the first movie," says Isaacs, who conjures the scene of Dumbledore using it to douse streetlights and leave orphan Harry on a doorstep undetected.

 Why does Harry not kiss Hermione while slow-dancing to Nick Cave's "O Children" but does kiss his Snitch (basically a golf ball with dragonfly wings)? Because, as this disk clarifies better than the film itself, she loves their pal Weasley more, and Harry suddenly remembers he almost swallowed a Snitch in his first Quiddich match. "It's a great example of something from much earlier in the series that offers a clue to something much later," Isaacs says, "and that's why the whole thing is one giant jigsaw."

 Beside putting clues together, Maximum Movie Mode gives glimpses of the conventional making-of extras, which you can click to watch in full. A few extras are on the DVD, too, but not Maximum Movie Mode, nor the sneak peek of Harry Potter and the Deathly Hallows, Part 2, opening in July. Fans will snap up the Blu-ray/DVD/digital copy combo like a pack of ravenous Snatchers.

Warner Home Video, Blu-ray $35.99, DVD $28.98