In "Shrek the Third" there's a scene in which the frog King Harold (voice by John Cleese), ward boss of Far Far Away, is dying. He utters his last words, and then -- old joke for a new generation -- no, he's not dead, he's still alive, and says a bit more, and expires, but in fact ….

The scene's supposed to be funny but sad, too, and then in the funeral sequence the oh-so-not-quite-hip soundtrack fills the theater with "Live and Let Die." By that point you're thinking: Huh? The effect is very sour. Using Paul McCartney's Bond theme doesn't work as parody or sincerity or anything, really. The film has its moments but is similarly conflicted.

Uninterested in being king and freaked out about becoming a father, Shrek embarks on a quest with Donkey (Eddie Murphy, virtually sidelined) and Puss (Antonio Banderas, a bright spot) to locate Fiona's estranged cousin. He's a put-upon high school kid (voiced by Justin Timberlake, forgettably) with royal blood. Prince Charming (Rupert Everett) has other plans for Far Far Away and gathers together a mass of storybook villains to implement a takeover.

The earlier "Shrek" films operated on a mixture of revisionist fairy-tale sarcasm and just enough heart to get folks like First Lady Laura Bush in their corner, along with millions of media-saturated preteens. (Bush told one interviewer she adored the first one.) I doubt even rabid fans of the first two will consider "Shrek the Third" a worthy addition to the franchise. Some amusing bits pop up, as when Pinocchio starts spouting evasive lawyerspeak lest he be forced to tell an actual untruth. But director Chris Miller, one of several screenwriters into jokes about Hooters and dinner theater, lets the swamp thing of the title get lost in his own tale.

As before, the clinical, hyper-crisp computer animation style looks weirdly realistic even though the milieu is fantastical. This means when someone gets clobbered on the noggin you tend not to laugh. In visual terms little of the slapstick comes with the necessary imaginative distance, though if this calculated amalgam of snark and heart had more wit, you wouldn't think much about not loving the way it looks.