An extended preview of Harry Potter and the Half-Blood Prince ran on Sunday night during the premiere of the NBC miniseries Merlin.

Watch the clip here below.

The clip focuses on the dark elements of this sixth Harry Potter story, which sees the dark forces of the magical world crossover in our world, revealing themselves to “Muggles.” There’s also an emphasis on Harry himself as the “chosen one.” Those who know the story, know there’s a entire subplot on the light side, with all the romance amongst the teenagers of Hogwarts. There’s only a touch of that in this preview, which contains new footage from the film.

I think running this preview during Merlin was an interesting choice, since I’ve always thought Half-Blood Prince to be very Arthurian already. The opening scene of this preview and the scenes with Harry and Dumbledore in the cave remind me of Mary Stewart’s The Crystal Cave, where Merlin learns magic in the titular cave. The folks doing promo for Merlin saw a connection too, as they’ve been saying “long before Harry Potter” on their own preview.

Half-Blood Prince is probably my favorite book in the Harry Potter series with just the right amount of action and gravity balanced with the more light side of teenage life. Also, much is revealed in this story, too, about Voldemort’s past and Harry’s destiny.

Harry Potter and the Half-Blood Prince arrives in theaters July 15, 2009.

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