Harry is asked to deal with dangerous stuff in 'The Half-Blood Prince.'

As I glanced around at the army of pre-teens on hand for the sold-out midnight premiere of Harry Potter and the Half-Blood Prince, a strange thought occurred to me: Are these kids old enough for Harry Potter?

After all, since starting off as relatively benign kiddie fare, the Potter series has taken on increasingly weighty themes. While the first two films from director Chris Columbus found a young Harry and his friends on adventures filled with wonder and discovery, ever since Alfonso Curion's beautifully-shot Prisoner of Azkaban and Mike Newell's subtle Goblet of Fire, Harry's world has been marked instead by grief, sacrifice, and sexual tension.

In fact, much of the time Half-Blood Prince feels a few shades lighter than previous installments. Though adolescent sexuality is in full bloom in Prince, it's played far more innocently than Goblet's seething hints. And while Order of the Phoenix forced our heroes underground and into a paranoid distrust of authority, the reassuring presence of Harry's adult mentor is restored in this latest tale.

Which is not to say that Prince is a light film. All that "innocent" sexuality is shown to have some serious emotional consequences. And while Professor Dumbledore may be back at Harry's side, what he asks of Harry resonates with danger. And when we finally reach the two-and-a-half hour film's climax, we're treated to a brief but terrifying adventure and what may be the most pivotal — and poignant — moment in Harry's battle so far.

It's rare that any film series, especially one aimed at children, offers us characters that actually grow and mature. It's even rarer to find one with the courage to examine the cost of that maturity.