Harold and Maude meets Little Miss Sunshine (and perhaps a tiny bit of Howl’s Moving Castle?) in Moonbox Productions’ coming-of-age story (with a dark twist), Kimberly Akimbo. And while it doesn’t quite manage to meet the same emotional high notes as the two films it’s reminiscent of, this play makes up for it with key scenes and plenty of heart and humor.

Akimbo tells the story of a 16-year-old girl named Kim (Sheriden Thomas) growing up in New Jersey—but while other girls her age are looking forward to the future, Kim finds herself coming up on the end of her short life: She was born with a disease that makes her ages four times faster than normal.

In relation to the rest of her family, however, Kim is by far the most well-adjusted. Her mother, Pattie (Micah Greene), is a heavily pregnant hypochondriac with a sailor’s mouth and a propensity for accidents. Her father, Buddy (Andrew Winson), is an irresponsible drunk, and her Aunt Debra (Shana Dirik) is a homeless con artist responsible for a mysterious event that forced the family to pick up and move several months before the start of the play. Kim finds solace and acceptance—and even the stirrings of first love—in her classmate Jeff (Lucas Cardona), a hapless fellow outcast who has a charming obsession with anagrams.

Perhaps the most questionable aspect of the play is the nature of Kim’s disease. She has, to paraphrase Jeff, “something like Progeria, without the large forehead and nonexistent chin.” It seems to have no ill effects on her day-to-day functioning, despite her abbreviated lifespan. We never see Kim at school or interacting with strangers in public. Although the audience is told that the other girls her age “ignore her,” she never once expresses feelings of depression, anger, or despair at her apparent isolation.

For a teenage girl, Kim is incredibly—unbelievably—collected and mature. Her infrequent outbursts are primarily aimed towards her father—for example, when he makes embarrassing comments about her crush on Jeff—but in the context of her character they seem almost forced and hollow. Her condition serves not just as a visible sign of mortality, but as a more pronounced point of interest to the audience than the actions of anyone else in the play (at least until the denouement, when everyone’s strange behavior is somewhat explained).

The supporting characters are flawed, selfish people. Unfortunately, we wait for some sort of redeeming qualities in them that never seem to arrive. Buddy spends Kim’s birthday out drinking—in fact, any time he’s not on stage, he’s somewhere getting drunk—to the point where his alcoholism is the only fully formed trait his character has. Pattie is nine months pregnant, but smokes and drinks shamelessly while hurling insults at anyone unlucky enough to come within earshot. Debra has a pathological willingness to put anybody in harm’s way to meet her convoluted goals.

In the hands of a lesser actor, Pattie would be totally insufferable; but Micah Greene manages to make her abrasiveness oddly endearing instead of off-putting. Shana Dirik and Lucas Cardona steal whichever scenes they’re in, with expert comedic timing and delivery that transcends the prolonged melodrama into which the narrative sometimes sinks.

Akimbo succeeds the most in scenes where the players are all together, portraying the functional dysfunction of family life. Scenes that take place in Kim’s room, in particular, shine with brilliance: In one, the family gathers around her bed, eating belated birthday cake and playing a game together, casually reminiscing about the past; in another, a fast-paced game of Dungeons & Dragons is hilariously brought to life. These simple snapshots highlight the chemistry of the actors and momentarily distract from the flimsiness of their characters.

At its core, Kimberly Akimbo is a story about growing up. Surreal, darkly comedic, and quirky, it strives to examine how imperfect people deal with the sometimes tragic hand life can deal—but instead of changing and growing from their mistakes, they just seem to tumble over and over into unhealthy cycles. Stripped of the jokes and caricature-like characters, Akimbo would be an incredibly depressing story about child abuse and neglect. But, carried by a stellar cast of actors and a victorious finish, it manages to make itself worth sitting through despite its flaws.

MOONBOX PRODUCTIONS PRESENTS: KIMBERLY AKIMBO. BCA PLAZA THEATRE, 539 TREMONT ST., BOSTON. ALL AGES/$30-35/$15 STUDENTS. MOONBOXPRODUCTIONS.ORG