Following a mugging incident at New York's Grand Central Station, an innocent bystander (Kevin Spacey, "The Usual Suspects") is arrested by police who believe him to be under the influence of hallucinogenic drugs. We can understand why they think this, considering how the man politely informed them that he wears his dark glasses because "the light on your planet is really bright." And so Prot (as he identifies himself, pronounced as rhyming with "goat,") is shipped off to the Psychiatric Institute of Manhattan, where a weary workaholic doctor, Mark Powell (Jeff Bridges, "The Big Lebowski"), attempts to understand this man's so-called delusion.<br /><br />Prot's manner is courteous and cooperative. When asked why he believes he has been institutionalised, he matter-of-factly replies that it is because "you think I'm crazy." Within minutes, after satisfying his insatiable newfound hunger for Earth-fruit, the completely forthright Prot has revealed that he is an extraterrestrial from the planet K-PAX, which resides 1000 light-years away, circling the binary star system Agape and Satori located in the Lyra constellation. He also details how his infinitely-more advanced species has already mastered faster-than-light travel, through harnessing the energy of light, an accomplishment that is allegedly eons away for the human race.<br /><br />Powell is understandably very skeptical of these outrageous claims, though he is nevertheless fascinated by them, and commits himself to understanding how Prot came to believe such a thing. Meanwhile, Prot uses his time to observe his fellow patients in the psychiatric ward, eventually offering everybody around him something to live for, and hope of a cure. On July 27, Prot later reveals, he will depart again for K-PAX, and he can only take one human with him. Of what will actually happen on that date, nobody is certain.<br /><br />Originally slated to play Dr. Powell  with Will Smith as Prot  Kevin Spacey stepped into the main role when Smith had to withdraw from the film. You can tell that he had a lot of fun with his character, the completely matter-of-fact delivery of his sometimes ridiculous dialogue ("Your produce alone has been worth the trip") often eliciting genuine laughter. There is undeniable intelligence behind many of Prot's words, but logic maintains that he must be delusional... mustn't he?<br /><br />The audience is led back and forth between the possibilities  for the first segment of the film, we almost accept the possibility that Prot is an extraterrestrial (this is a sci-fi movie, isn't it?!), before being totally convinced when Prot inexplicably displays an impossible knowledge of the astronomy of a newly-discovered planet system. A final investigation by Dr. Powell offers us a neatly-packaged terrestrial explanation for Prot's delusions, but this is just as quickly whisked away, and we are left scratching our heads again. The film, quite rightly, keeps its ending open, leaving the audience to contemplate what they've just watched and to discuss it with those around them. Nevertheless, whether you believe Prot to be an alien or not, two irresistible certainties linger in your mind: the Universe is, indeed, a fascinating place, and perhaps there are higher forces that we humans are yet to discover.