(CNN) -- The end is closer than the beginning.
Ron (Rupert Grint, left), Harry (Daniel Radcliffe, second from right) and Hermione (Emma Watson) in the new film.
Harry Potter and his friends at Hogwarts are now in their sixth year of seven at the school. They've seen a lot of changes, particularly as the influence of the reawakened Voldemort (that is, He Who Must Not Be Named) has made itself known.
And the movie series itself is now nearing its conclusion. "Harry Potter and the Half-Blood Prince," which comes out Wednesday, is likewise the sixth movie in the series based on J.K. Rowling's seven Harry Potter books.
There is one benefit to having such history, director David Yates says: Pretty much everybody going to see "Half-Blood Prince" is familiar with the characters, whether through the books or the movies.
"We made a decision -- we kind of crossed a line, actually, I think, on this movie, where we said, 'You know, this is the sixth one in the series; it's the most popular franchise probably in history; do we stop and explain things to the audience who may have not seen any of the others?' And we said 'no,' " Yates said. "And you know why? It's because they can always go back to DVDs. They can go back to the books."
Indeed, many fans know the books -- and the movies -- backward and forward. Interactive: Harry Potter 101 »
The new film reflects the growth of the characters: Harry, the orphaned boy wizard who has been forced to take on responsibilities beyond his youthful years; Ron Weasley (Rupert Grint), his red-haired best friend, who is finding depths of courage in himself he wasn't aware of; Hermione Granger (Emma Watson), the bookish and indispensible member of their clan, who has demonstrated key leadership qualities; and all the rest, preparing for the showdown with the archvillain Voldemort. Watch the Potter cast answer your questions »
Among the returning performers: Michael Gambon as Dumbledore, Alan Rickman as Snape, Maggie Smith as McGonagall, Robbie Coltrane as Hagrid and Ralph Fiennes as Voldemort. One addition is Jim Broadbent, who plays Horace Slughorn, a former professor brought back to Hogwarts. Watch the stars at the rainy premiere »
Despite the growing darkness, there's also a lightness to the new film, says Daniel Radcliffe, who plays Harry. Unlike the previous two movies in the series, which were rated PG-13, this one is rated a more family-friendly PG.
"I think this film's funnier," Radcliffe said. "There are a couple of moments which I laughed out loud at."
Not that it's going to be a barrel of laughs, Yates cautions. (How could it, with the snake-faced Voldemort growing ever stronger?)
"It is a bit bipolar," Yates said. "On the one hand, there's all this ... romance, and on the other hand, people are getting killed, and bridges are being blown up."
Oh, yes, there's romance. After all, the main Potter characters are all teenagers now, with all the teenage longings.
Potter fans have had their own longings. "Harry Potter and the Half-Blood Prince" was scheduled to be released in November but was pushed back to its Wednesday opening after Warner Bros., Potter's studio, expressed concerns about putting it out over the holiday season. (Warner Bros., like CNN, is a unit of Time Warner.)
Warner Bros. said at the time that the film "perfectly fills the gap for a major tent-pole release for mid-summer" and added that the delay was also due to "repercussions" from the 2007-08 writers strike.
But fans weren't so easily placated, filling message boards with angry comments and starting petitions that garnered tens of thousands of signatures. Warner Bros. President Alan Horn was even moved to put out a statement assuring fans that the scheduling change "was not taken lightly."
Now that the moment is finally at hand, the fans seem to have forgiven the studio. According to Fandango.com, a movie ticket-selling site, "Harry Potter and the Half-Blood Prince" is outselling "Transformers: Revenge of the Fallen" at the same point in the sales cycle. It's also in MovieTickets.com's top 25 advance sellers of all time.
Given that "Transformers" is, by far, the year's top-grossing film, those tidbits can't help but make the studio happy. iReport.com: Seeing the latest "Potter?" Share your review
The last of Rowling's Potter books, "Harry Potter and the Deathly Hallows," is in production now as two films. That's given the cast a bit of temporal whiplash when talking about "Half-Blood Prince," since they completed it more than a year ago, but they've been game to talk.
After all, they've come a long way since "Harry Potter and the Sorcerer's Stone," way back in 2001. And they're aware as anyone of the passage of time -- that they're closer to the end than the beginning.
It's the kind of situation that leads to sentimental reflections. But Watson, for one, couldn't wait to let go of one thing: her school uniform.
"I was like, 'Burn it!' " she told Entertainment Weekly. "Oh, my God, to be done with those shoes and that uniform -- that was an exciting day."