"He's faced giant snakes, ghastly Dementors, and the minions of the villainous Lord Voldemort. But teen love? Now there's a menace worthy of Harry Potter's mighty wand. "Hormones are indeed raging. It's like The O.C. here," reports producer David Heyman from the set of Warner Bros.' fourth Potter film. Both Harry (Daniel Radcliffe) and pal Ron (Rupert Grint) start seeing the opposite sex in new ways.

The plot has Harry in a tournament against other wizarding schools--our first real glimpse of the magical world outside Hogwarts--and bad things are happening, leading to the return of He Who Must Not Be Named (a.k.a. Voldemort, played by Ralph Fiennes).

Succeeding Chris Columbus and Alfonso Cuaron as director is Mike Newell--and before you start saying What the bloody heck is the man who made Four Weddings and a Funeral doing here?, remember: He made the well-regarded (if little-seen) kid adventure Into the West and the tense Donnie Brasco. "And he's British. We thought it'd be fun to try that for once," quips Heyman.

Fans can also anticipate fire-breathing dragons, an underwater rescue, and a killer hedge maze--and we mean killer. "It's fantastic," raves 15-year-old Radcliffe. "I can't wait to get the videogame for this one."

Books of 2005, bow before your master: Harry Potter and the Half-Blood Prince, due July 16, will be the best-selling tome of the year.