In a summer of remakes, reboots and sequels comes "Inception," easily the most original movie idea in ages.

Now, "original" doesn't mean it's chases, cliffhangers, shoot-outs, skullduggery and last-minute rescues. Movies have trafficked in those things forever. What's new here is how writer-director Christopher Nolan repackages all this with a science-fiction concept that allows his characters to chase and shoot across multiple levels of reality. This is, in some ways, a con-game movie, only the action takes place entirely within the characters' minds while they dream.

Following up on such ingenious and intriguing films as "The Dark Knight" and "Memento," Nolan has outdone himself. "Inception" puts him not only at the top of the heap of sci-fi all-stars, but it also should put this Warner Bros. release near or at the top of the summer movies. It's very hard to see how a film that plays so winningly to so many demographics would not be a worldwide hit. It opens in North America on July 16.

Not that the film doesn't have its antecedents. "Dreamscape" (1984) featured a man who could enter and manipulate dreams, and, of course, in "The Matrix" (1999) human beings and machines battled on various reality levels created by artificial intelligence.

In "Inception," Nolan imagines a new kind of corporate espionage wherein a thief enters a person's brain during the dream state to steal ideas. This is done by an entire team of "extractors" who design the architecture of the dreams, forge identities within the dream and even pharmacologically help several people to share these dreams.

A good deal of the 149-minute film's first hour is spent, essentially, selling the audience on this sci-fi idea. As you witness an extraction that fails and then Dom's recruitment of his new team around the world, the movie lays out all the hows, whys, whos and what-the-hells behind "extractions."

Leonardo DiCaprio plays Dom Cobb, a master extractor, who is for what initially are vague reasons on the run and cannot return home to his children in the States. Then along comes a powerful businessman, Saito (Ken Watanabe), who offers Dom his life back -- if he'll perform a special job. Saito wants Dom to do the impossible: Instead of stealing an idea, he wants Dom to plant one, an idea that will cause the mark, Robert Fischer (Cillian Murphy), to break up his father's multibillion-dollar corporation for "emotional" reasons.

Meanwhile, you meet the other team members -- Arthur (Joseph Gordon-Levitt), Dom's longtime point man; Eames (Tom Hardy), the forger; Yusuf (Dileep Rao), the chemist; and Dom's father-in-law (Michael Caine), who is not on the team but the professor who taught Dom to share dreams. Dom's late wife, Mal (Marion Cotillard), haunts his own dreamworld like a kind of Mata Hari, intent on messing with his mind if not staking a claim to his very life. He doesn't let on about this, but Dom's new architect, Ariadne (Ellen Page), figures it out -- which makes her realize how dangerous it is to share dreams with Dom.

If you don't follow all this, join the club. It will perhaps take multiple viewings of these multiple dream states to extract all the logic and regulations. (At least that's what the filmmakers hope.) Something else might come more easily on subsequent viewings: With incredibly tense situations suspended across so many dreams within dreams, all that restless energy might induce a kind of reverse stress in audiences, producing not quite tedium, but you may want to shout, "C'mon, let's get on with it."

This is especially true when the hectic action in one dream, a van rolling down a hill with its dreamers aboard, causes a hotel corridor to roll in another, producing a weightless state in the characters. Even Fred Astaire didn't dance on the ceiling as much as these guys do.

Probably what "sells" this tricky movie is the actors. In his second consecutive movie to question reality -- "Shutter Island" came earlier this year, remember -- DiCaprio anchors the film with a performance that is low-key yet intense despite hysterical chaos breaking out all around him. Page too displays sharp intelligence and determination in the face of this absolute jumble of reality. Especially surprising is Murphy as the mark; you find yourself genuinely sympathetic to a guy who just wanted to catch a little shut-eye and finds his mind kidnapped.

It also is nice that Nolan strives to keep CG effects to a minimum and do as many stunts in-camera as possible. This photo-realism certainly helps to keep the dream realities looking more plausible. Credit cinematographer Wally Pfister with so neatly blending the real and surreal without any hokey moments. Ditto that for production designer Guy Hendrix Dyas and the various stunt coordinators and effects teams. Meanwhile, editor Lee Smith does a Herculean job of juggling those different realities. Sometimes originality comes at a cost though: At the end, you may find yourself utterly exhausted.