A young man on a stage finger-paints the universe. He reduces nebulae, black holes and novas to identical childish blobs. Then the juvenile artist crumples the page — literally adding another dimension to the piece.

This scene, the opening of the endearing “I’m From Outer Space,” also crudely illustrates the play’s central conceit: a honeyed, innocent day in the life of Jason (Josh Stein ’13), wide-eyed kid and existentialist space alien growing up in a suburban family on Earth.

The supposed teen’s vocabulary seems better suited for the elementary-school set (his psychiatrist mother wants to give him “happy pills” and all his meals are supervised), except when he’s doodling quantum equations in his notebooks, and the dialogue would come off as condescending if it weren’t for a few redemptive moments of wry self-awareness. By the hour’s end, predictably, Jason learns something about himself and the humans closest to him. How do you say ‘bildungsroman’ in Klingon?

The action of this sci-fi After-School Special takes place entirely in the 24 hours before our extraterrestrial hero leaves home — the U.S. — for France, where he plans to study art (read: finger-painting). Ulysses, it’s not. But with a smattering of deep thoughts and allusions to rocket science, Tim Duncheon ’10 keeps the script from dissolving fully into a particularly syrupy episode of “Third Rock From the Sun.” (That would be the 90’s sitcom that gave us Josh Gordon-Levitt. Thank you.)

Throughout the farewell montage, in a tour de force of costume changes and kinetic energy, Katharine Pitt ’12 and Alex Steiner ’13 alternate as Jason’s parents, schoolyard friends, crime-fighting space hero companions and clones, among other roles. Signature facial hair and props help the audience keep track of the characters, but Jason also explicitly narrates every scene, just in case.

Towards the end of the piece, when the protagonist manages to hold a conversation with another character for more than a few lines, he takes a breath, then deadpans, in a whisper: “It’s funny how quiet it is without all that narration,” — a refreshing and well-timed meta-nod to the audience’s patience. Also an on-point identification of one of the play’s weaknesses.

But for what is essentially an extended monologue, the play never drags or slackens. Credit here goes to the cast’s unfailingly snappy delivery and the smooth direction of Moses Balian ’13. Even Jason’s spacey girlfriend Annie (Margot Mellette ’14) keeps the pace in her scenes, while adopting a Luna Lovegood-esque lilt and conveying a head-in-the-clouds personality.

Annie delivers some of the play’s most earnest, heart-felt lines: “So much that’s important is left unsaid these days. I don’t think we should let it all be implicit,” and — critiquing Jason’s idealized memory, “We don’t talk like that most of the time.”

While the sentiments are admirable, the last third of “I’m From Outer Space” may follow its own advice a little too closely, reciting lessons when the viewer has already absorbed the theme. Rather than explaining that fractals demonstrate how “the littlest part of the story tells the whole,” Jason could let the image speak for itself. The play is strongest when adhering to its oddball premise, rather than translating it into our terrestrial vernacular. The language may be alien to us, but the message is universal.