Campbell Scott stars as Joe Ross, a bespectacled scientist-of-sorts who is also a brilliant mathematician. He's also the inventor of the Process, an invention that will make his company more lucrative than ever before.

Ross's boss, Mr. Klein (a laid-back Ben Gazzara), is so impressed by the Process that he holds a meeting in the Caribbean to discuss its future - a company lawyer (Ricky Jay) is on hand to look after the finances. On the Caribbean, Joe meets a typical Mamet character named Jimmy Dell (Steve Martin) who offers Joe one-thousand dollars for his watch - this is the kind of request that should drive Joe away from Jim not towards him. Denying his request, Joe decides to accept Jim's dinner invitation in exchange for his apologetic remarks.

Naturally, Jimmy Dell is the driving anchor of the movie and it would be unfair for me to explain what the plot's surprises have in store for you. Suffice to say, if you are a Mamet fan you'll anticipate many of the twists and turns the plot takes. If you have seen the Mamet-like labyrinth "The Game," you'll see some distinct similarities.

Surprisingly, "The Spanish Prisoner" works because of its characters and the sharp dialogue rather than the elaborate machinations of the plot. Joe Ross is the bland every man whom things happen to and not always for any clear reasons. As played by Campbell Scott, the character is broadly sketched displaying no apparent flaws or weaknesses except that he's too trustworthy. In other words, he's a cipher - a trait uncharacteristic of Mamet - but Scott manages to bring some droll, subtle humor to Joe's character.

Two of the finest performances in the film are by Steve Martin and Rebecca Pidgeon (Mamet's wife). Steve Martin gives a superb, restrained performance as the seemingly rich New Yorker who asks for other simple services of Joe such as sending a book to his sister in New York. Is that all Jim wants, or is he up to no good? Martin's poise and mannered speaking are as fluent and as engaging as anything he's done in his career.

Rebecca Pidgeon (an accomplished singer in real-life who also starred in Mamet's "Homicide") plays one of the sweetest, smartest women in all of Mamet's works. Her character, Susan, Joe's secretary, bears a certain affection to Joe that leads to all kinds of plot turns. Susan is sexy, intelligent, convivial, a bit annoying in the beginning but we grow to like and accept her, and is manipulative and perhaps deceitful, but we are never sure. My two favorite scenes with Pidgeon are the airplane scene, where she discusses how you never truly know the people in your life, and a hilarious moment where she fabricates an argument with Joe to evade questions from the police.

"The Spanish Prisoner" is in many ways both akin and atypical of Mamet's former films. For one, the film is rated PG. Gone are the customary four-letter words we normally associate with Mamet and, as a result, it's also more light on its feet and less heavy than usual. Part of its lightness comes from the greenish, mossy look of the cinematography that fits perfectly with the title and the mood. Although the film is occasionally flawed and unevenly paced, "The Spanish Prisoner" is still high quality verbal entertainment. From Mamet, I wouldn't have expected less.