After claiming he is an extraterrestrial from the planet ‘K-PAX’, 1,000 light years away in the Lyra constellation, prot (uncapitalized and rhyming with “goat”, played by Kevin Spacey) is committed to the Psychiatric Institute of Manhattan.

There, psychiatrist Dr. Mark Powell (Jeff Bridges) attempts to cure him of his apparent delusions. However, prot is unwavering in his ability to provide cogent answers to questions about himself, K-PAX and its civilization. Dr. Powell introduces him to a group of astrophysicists, to whom prot displays a level of knowledge that puzzles them…