It's a fairy tale we've all heard before.

Producer meets script. Producer takes script on a whirlwind journey through characters, animation directors and musical scores straight to box office success. After the first hit, producer takes script, tweaks it and sends it back to hungry audience. They love it again, so dear producer decides to go for success one last time.

Except this time, the story is tired, the jokes are banal and the once-beloved characters stop being funny and start being really, really annoying.

This is the fate of Shrek the Third, a movie with much promise and little follow-through. The film starts out just after the last one left off – ogres Shrek and Fiona (voiced by Mike Myers and Cameron Diaz), the prince and princess of kingdom "Far Far Away" fill in for king and queen when Fiona's Frog-King Harold father takes ill.

Before the King croaks, he tells Shrek to take the throne or find Arthur (voiced by Justin Timberlake) – the only remaining heir. Desperate to leave the posh ways of the kingdom, Shrek goes off in search of Arthur, an angsty teenage version of the legendary King. Meanwhile, Fiona deals with her pregnancy and battles Prince Charming (Rupert Everett) and his band of storybook villains.

But despite a plot with so much potential, Shrek fails to entertain. The blame lies primarily on the characters. The goofy Donkey (voiced by Eddie Murphy) is now a father with grotesquely cute dragon-donkey children, but his once hilarious antics are now trite. What caused tears of laughter the first time, or even the second time ceases to amuse the third time around, and audiences aren't likely to exit the theater with something to laugh about after the film ends.

The movie also falters when it goes too far to parody every fairy tale possible. Nearly all of the princesses – Sleeping Beauty, Cinderella, Snow White and even Rapunzel make an appearance, as do several wicked witches, Captain Hook and a crazed, Birkenstock-clad Merlin. In this ambitious attempt to satirize well-known fabled characters, the movie fails to create any quality parody, unless you count Cinderella's penchant for cleaning the floor as funny.

In fact, Shrek The Third's only redeeming quality is the ogre himself. Throughout the movie, the audience gets to appreciate Shrek's tender, loving side – whether it be his worries about fatherhood or his love for Fiona. The ogre matures into wiser man, dispensing invaluable advice to young Arthur.

But large as he may be, even Shrek cannot make up for his film's pitfalls. Young children might be entertained by the abundance of crude humor characteristic of the movies, but older audiences won't be smiling when Donkey cracks the same joke for the billionth time.

Shrek the Third is rated PG for crude humor, suggestive content and swashbuckling action. It is now playing in theaters everywhere.