A strange stranger appeared at the Central Park station in New York, and said in front of everyone that it came from another planet: K-PAX. The police who heard the news believed that he was insane, sent him on the train to the mental hospital, and entrusted him to Mark (Jeff Bridges), a kind psychiatrist. The patient called himself Prot (Kevin Spacy), an optimistic and confident guy. In the hospital, he talked to patients and doctors about his life on the planet K-PAX 1,000 light-years away. His description is so vivid and nuanced that it puzzles Mark, but it brings hope to other mental patients. What's even more amazing is that some patients' conditions have improved under the influence of Prot. Even Dr. Mark himself feels that through contact with Prot, he has overcome self-doubt and learned to express his inner feelings to his loved ones.
Prot announced that he would leave Earth at the end of summer and return to planet K-PAX. The patients rushed to express that they wanted to go with him. The scheduled departure day is getting closer and the patients are getting more and more excited because of the upcoming opportunity to contact aliens, but Dr. Mark is caught in a puzzle. Is Prot a mental patient? Should you believe in your own scientific diagnosis, or should you believe in Prot's confident statement? Mark even had doubts about his ability to distinguish reality from fantasy.
