Psychiatrist Gene Brewer doesn't have a diagnosis for the mysterious new patient who calls himself "prot" (rhymes with goat). But this strange and likeable man cannot be—as he claims—from the planet K-PAX.

Or can he? Prot knows facts about space that confound experts. He soon reveals Dr. Brewer's own deepest pains and most sublime longings. And his tales of K-PAX have other patients competing to go along with him when he heads "home".

Now the doctor is racing the clock to find prot's true identity before he loses a man whose "madness" might just save them all . . .