In the traditional telling of "Ali Baba & the Forty Thieves," the plot is fairly straightforward. Heroic Ali Baba overhears the secret password, raids the thieves lair and then scalds them to death while they sneakily plot to avenge their gold and jewels. Obviously an exciting tale -- the first few times it's presented. But what if one day Akram the Terrible, indomitable leader of 39 obtuse robbers, recognizes the pattern of the narrative and decides he doesn't want to be a "baddie" any more?

In Open Sesame, British humorist Tom Holt, with ample aid from storyteller Scheherezade, blurs the divisions between fiction and reality, hero and villain. Both Ali Baba and his nemesis Akram, guided by a bear and their fairy Godfather ("Three wishes you can't refuse"), flee their storyland roles for more mundane existences in dentistry and culinary arts. (Talent with a knife is a useful career skill.) While they attain some levels of freedom from plot devices, they don't entirely escape their roles as enemies or their characterizations from the old country. Their inevitable encounters and subsequent intentions regarding revenge make for some very entertaining reading.

Holt's supporting cast of characters are equally complex and delightful: Michelle overcomes her initial reluctance and spends quality time with her family of bickering kitchen gadgets. Fang, the avaricious tooth fairy, recognizes the value of merchandise other than molars. The thief from a family of largely unsuccessful crooks, John Fingers Smith, enjoys the lush Arabian life -- for a while -- when he thinks he's finally made the big time.

The 39 bumbling burglars, who are distraught at the disappearance of their beloved "Skip," the only one who knew the accounting procedures and the location of the hideout, wreak havoc as they search for him throughout favorite stories. (They're especially harsh toward animals, and Rapunzel apparently let down more than her hair.) Setting the book on both sides of the line dividing reality and fiction yields opportunities for delicious cameos from many memorable characters.

The plot of Open Sesame goes beyond twisting into diving and frolicking as heroes and villains interchange perceptions, shadows and sidekicks while struggling between the control of a story and their desire for free will. The ending includes a confusing array of oil jars and flashbacks, but it isn't distracting enough to divert the reader from the exquisitely developed characters.

Holt fans will appreciate inside jokes and allusions to earlier novels. A talking gun reminiscent of My Hero is joined by a cadre of communicating electrical appliances and traffic signals. And, of course, as all readers of Tom Holt's punnish dialogue know -- sometimes a door isn't a door.

It isn't necessary to have read earlier novels -- or even Tales from the Arabian Nights to appreciate the clever dialogue and realistic fictional characters in Open Sesame.