In “King of California,” a self-reliant teenager (Evan Rachel Wood) holds down the family mortgage without need of parental oversight until her dope-smoking, jazz-playing, free-spirited father (Michael Douglas) shows up newly released from a mental spa, begging her to stay out all night with him on a quest for buried treasure. The movie insists on presenting this situation as bittersweet, if comic, drama, intended to be at least slightly moving. I wouldn’t argue, however, with a dad or teenager who simply called the arrangement “sweet.”

At least subconsciously the movie seems to agree, though it is ever vigilant with its message of familial mending. If you can get over this bait and switch, however, the charming if undemanding story unfolds at a sprightly pace. Miranda (Wood), at first annoyed by Charlie’s (Douglas) newfound eccentricity, gradually warms to the idea of spending long days and nights surveying and digging across Southern California. The two are on a hunt for millions Charlie believes an obscure Spanish explorer left under a local Costco.

Though Wood, cast in the lead, might seem a natural fit for a look at postmodern family life, Douglas slyly steals every scene he’s in. Sprouting facial hair like a Chia Pet and with the googly eyes of Groucho Marx, his brightly burning crazy man withers Wood’s jaded anti-teen, making one wish in vain for an actress who had more to stand on than pretty eyes and a pouting lip.

Douglas is brave enough to throw his Hollywood leading-man image out the window for a project that doesn’t always have his back. Atypical for a film with Alexander Payne’s name attached to it (the “Sideways” director co-produced), “King” overturns realism with whimsy whenever the going gets tough. The movie reaches for sentimentality at the end, but it’s hard to buy. As a first-time effort (from writer-director Michael Cahill), the movie is a cute, mild diversion. Aspirations of royalty beyond the title, however, are completely delusional. (PG-13)