Based on a novel by Gene Brewer, K-PAX works best as an adult drama of self-discovery, blessed by the talents of costars Jeff Bridges and Kevin Spacey. Bridges plays Manhattan psychiatrist Mark Powell, who thinks he's seen it all until he's assigned to analyze Prot (Spacey), a psychiatric patient who claims to be from a distant planet called K-PAX. Powell is convinced that Prot is a convincing delusional, but his cynicism turns to open-minded fascination as Prot's case reveals a combination of otherworldly insight and all-too-human trauma, prompting an earthbound explanation for Prot's allegedly alien origins. As directed by Ian Softley (Wings of the Dove), this curiously engrossing drama allows Spacey to create a provocative and humorously eccentric enigma, while Bridges superbly conveys his character's compassionate empathy. Their finely shaded performances raise K-PAX above the forced ambiguity of its ending, which is both thought-provoking and vaguely anticlimactic.