How refreshing it is to see a child acting unpredictably on a movie screen, and even nicer to see a child prodigy depicted as something other than a foregone conclusion. To tell you that “Vitus” is about a brilliant child pianist who decides one day that he’s fed up with the way his hobby has come to dominate his life — his mother berating him to practice, quitting her job to focus more on developing her son’s “career” — would suggest a typical sort of child in a very typical sort of movie.

“Vitus,” though, much like its lead character, is a film with tricks up its sleeves. Not “tricks,” as in surprise endings or double-crosses, but tricks that make a character into something more than just an artificial construct; a character who seems able to think and act on his own terms.

For the more we think we have 12-year-old Vitus (real-life prodigy Teo Gheorghiu) figured out, the more he strays from the path we expect him to take. One such magical moment occus when this preteenager takes a girl to dinner — the girl who used to baby-sit him — and professes his undying love for her. It’s a reckless moment, an absurd statement, professing an emotion that he can’t possibly understand to a girl he can’t possibly expect to win.

But Vitus does it, and it’s enough to make one sit up straight and look at the boy in a new light. He’s a 12-year-old romantic with guts to match. In this moment, he grows before our eyes, and the film becomes an organic experience, not just filling in the outlines but redrawing the boundaries of where the boy — and the movie — may go.

Not that things don’t start in familiar territory. We first meet a 6-year-old Vitus as he bangs away at a piano and wows an unsuspecting audience at one of his parents’ dinner parties. He then eavesdrops as the guests warn his parents that they had better “nurture” the talent. Expectedly, the nurturing is undertaken in unhealthy ways, as Vitus increasingly finds himself berated by his mother (Julika Jenkins) and isolated from his friends. Early on in the film, he is taken to an important recital, but rather than playing in the hope of earning admission to a prominent program, he throws the audition. On the way home, his mother tells him that she will never forgive him for his betrayal.

Thus, the child prodigy story ends abruptly. In its place emerges a coming-of-age tale that intertwines not only with a story about a family in crisis, but something of a medical mystery. Swearing that he has suddenly lost his ability to play the piano, Vitus may be lying to free himself from his parents’ expectations. As he grows older, Vitus begins to look beyond himself and registers the hardships facing his father (Urs Jucker), who’s mired in career struggles. All the while, Vitus’s passions drift from pianos to computers, from music to the stock market. He hides his true thoughts and feelings from everyone but his grandfather (Bruno Ganz), the only person who has always let Vitus be Vitus.

Director Fredi M. Murer manages to imbue his film with an unassuming melodrama that doesn’t dare present the world of professional pianists, or the tortured teenager, in finite dimensions. Watching “Vitus,” it becomes clear how arrogant and smug most films are, and how skeptically we often approach movies, wary of really engaging a work that may let us down with a predictable outcome.

On the contrary, “Vitus” (and Vitus) doesn’t pretend to have it all figured out, and is therefore set free from the conventions. The film moves at the whim of the character, making it difficult to anticipate its surprises or judge its decisions, as it would be difficult to foretell or judge a person’s decisions about how to live his life.

It all comes down to the young Mr. Gheorghiu, who taps his own remarkable knowledge of the piano to help us see the conflicted heart of Vitus — a child without strong roots in the process of building a real foundation. Indeed, by the end of the film, we’ve nearly forgotten all about his God-given talent. He’s simply a fascinating person, someone we can think of as a friend and come to respect so much that any ending to “Vitus” would be the right one.

ssnyder@nysun.com