On the surface, Setsuko Kawashima’s life looks quite simple. She has a job (doing something for a Tokyo company that does something else, but what, exactly, isn’t quite clear). She has a niece she dotes on and a sister she avoids, mainly because the sister stole and married Setsuko’s boyfriend, a fact Setsuko brings up every time her sister’s name is mentioned. Then one day, on her way to work, an unknown man whispers “goodbye” to her, then throws himself on the train tracks.

“Oh Lucy!,” from Japanese writer-director Atsuko Hirayanagi, is about what’s hidden — and what emerges — when Setsuko (Shinobu Terajima) finds a little bit of freedom from her life of routine. When her niece can no longer afford the English classes she’s been taking, Setsuko reluctantly agrees to attend in her place. When the instructor, John (Josh Hartnett), a gregarious American with a penchant for awkwardly long hugs, hands her a box of American names, she picks “Lucy.” (For unknown reasons, he also gives her a fuzzy, frayed blond wig.)

As Setsuko becomes less Setsuko and more Lucy, her world begins to open up: She begins a flirtation with a fellow student, gets embarrassingly hammered at a karaoke-focused retirement party, and, when her niece suddenly leaves for America, sets off with her sister to find her. John, who has since returned home, becomes their reluctant tour guide and translator.

The closed-in sense of Setsuko’s life in Japan — Hirayanagi keeps the lighting either drab or dim in these scenes — contrasts with the wild, wide-open California dreaming of Lucy’s American adventure. She tries pot. She gets a tattoo. She is introduced to the world of automotive sex. Like any convert, she also takes her new life to sometimes troubling extremes.

Terajima renders Setsuko’s transformation as a slow but inevitable burn. With her voice hovering just above a whisper in her early scenes, her eyes do most of the work. As she progresses, it gets louder, and she starts to shine with a wicked confidence and humor. The role of John, though underwritten, is a swaggering embodiment of Americanness, yet Hartnett never lumbers into caricature.

(Bonnie Osborne | Film Movement) Josh Hartnett is a sunny English tutor who becomes a reluctant tour guide in "Oh Lucy!"

As Setsuko’s judgmental, meddling sister, Kaho Minami delivers a performance that illuminates their strained yet nonconfrontational relationship. The sisters’ plane ride to America, where they sit flanking an American woman (Megan Mullally), begins with polite, halting conversation but ends with Setsuko blurting out, “She stole my boyfriend.”

All this before takeoff.

“Eat Pray Love” this isn’t. Although Lucy is on a journey of self-discovery, she often hurts others in her quest for herself. That makes Hirayanagi’s take on the later-in-life coming-of-age story more honest than most. The filmmaker doesn’t shy away from showing the negative consequences of Lucy’s actions, but neither does she judge them.

If Setsuko was once cautious and insecure, living for others, because she was ashamed of herself, Lucy is a blond bulldozer, becoming interested only in what she wants. All the while, we — and she — aren’t sure whether “Lucy” is becoming more herself or transforming into someone she was never meant to be.

★★★

Oh Lucy!

When • Opens Friday, March 23.

Where • Tower Theatre.

Rating • Unrated; contains drug use and sex.

Running time • 96 minutes.