Once in a while, an actor comes along with a natural talent that can carry a film that would otherwise be unwatchable. Not that Candice Mana Ono’s debut feature “Lovely Little Ai” falls into that category, but this quirky, patchy coming-of-age movie is a showcase for star Akane Sakanoue, playing a teen a decade younger than her 26 years.

Appearing in almost every scene, Sakanoue performs the title character’s transition from a good-girl loner to a free-spirited social butterfly with no signs of strain, in contrast to some of her scenery-chewing fellow thespians. As the film begins, protagonist Ai could be labeled a Japanese version of Hollywood’s manic pixie dream girl: Cute, odd and effervescent. But as played by Sakanoue, she begins to develop a will of her own, going beyond stereotypes and never becoming an annoyance.

Since the death of her mother shortly after her birth, Ai has been raised by her controlling salaryman father (Kan Hotoda) who imposes strict rules — 6 p.m. curfew, do nothing without Dad’s permission, etc. — that she follows to the letter, leaving her friendless. Despite his rigid control, her workaholic father is almost entirely a no-show in her daily life, which makes her lonely.