Lulu Wang had a story to tell: A few years ago, her father’s mother, whom Wang calls Nai Nai, had been diagnosed with Stage 4 lung cancer and was given just three months to live. Believing the emotional jolt would only summon her fate, the family kept the diagnosis a secret from Nai Nai and hastened her grandson’s planned wedding so everyone had a reason to visit China and see her once more.

The story, Wang believed, could make for a tender, lightly comical film about the lengths we go to protect one another. It could fold in the ethical turmoil of a Chinese American woman struggling to say goodbye within what she initially considers to be the confines of unfamiliar cultural norms. But potential financiers wanted a “big, broad, ethnic comedy,” the director recalls on an early July afternoon. No dice. She ultimately decided to set the project aside — until she was approached by Neil Drumming, a producer on NPR’s “This American Life” and a filmmaker.

“He was like, ‘You’re a woman of color in Hollywood. What stories do you want to tell that no one’s letting you tell?’” Wang says. She narrated a nearly half-hour autobiographical segment about Nai Nai that the radio program aired in April 2016. Within 48 hours, movie producers were clamoring for her version.

“The Farewell,” which opened with the best per-screen average of the year, is the understated film Wang had long envisioned. Whereas skeptical producers once wondered whether her screenplay would make for an American or a Chinese release — “which is a very confrontational question . . . that’s basically saying to me, are you American or are you Chinese?” — Wang’s finished product is, in that respect, a shoulder shrug. She’s both. Her movie stand-in is a New Yorker named Billi (Awkwafina) who visits her grandmother in Changchun. That’s where the real Nai Nai still resides — still unaware of her diagnosis — and where Wang lived until moving to Miami at age 6.

Like Billi, Wang never had anyone who shared her first-generation perspective of the family’s decision to keep Nai Nai in the dark. There were moments when she wanted to be able to turn to someone who could validate how funny, odd or almost surreal certain interactions with Nai Nai or her other family members were. In the film, Billi fluctuates between spiritedly joining her grandmother (Zhao Shuzhen) in practicing tai chi and wallowing in her feelings of isolation during tense dinnertime discussions. She wonders whether the family’s charade strips Nai Nai of her own right to say goodbye.

While Billi’s father (Tzi Ma) seems similarly forlorn at times, Billi’s mother (Diana Lin) at one point chastises her daughter for suggesting that she be a little more sensitive about her dying mother-in-law: “What do you want from me?” Billi’s mother demands. “To scream and cry like you?”

Wang adds, “When I would turn to my parents and be like, ‘This is crazy,’ they’d be like, ‘What’s so crazy about it?’ If people keep saying that to you . . . you don’t know when to trust yourself. You don’t know where you belong in your family, almost. This time, going back to make the film, I had all of these people who saw this experience from my eyes, and that were there to make a film through that perspective.”

Working on “The Farewell” was enlightening for Wang, who, from the remove of a screenwriter, could this time more closely examine how each of her family members might have felt during their visit to Changchun. She describes one of the film’s major themes as “the performance versus the personal” — performing joy for Nai Nai, for the sake of organizing a wedding, versus dropping the facade and letting their true emotions take hold. Conversing late at night, Billi’s father and his brother confront the fact that their mother had grown old without the comfort of living near her sons, who moved to the United States and Japan, respectively; Billi’s cousin sobs at his own wedding banquet, overcome with grief.

“I wanted to make sure that everyone was three-dimensional,” Wang explains. “Whatever their beliefs are, whatever their intention and perspective is, at the end of the day, they’re heartbroken. And that’s the thing that binds everyone together — that they all spent this time trying to figure out what the best thing is to do, but at the end of the day, everyone has to let go. There’s no other choice.”

The climax of Billi’s emotional arc arrives suddenly, as she and her mother search for a lost earring. She breaks down while on her hands and knees, vocalizing how lost and broken she felt as a child after moving to the United States. Wang tweaked her story quite a bit for the film. In addition to lowering Billi’s Mandarin proficiency to match Awkwafina’s skill level — “My family would joke and be, like, ‘She’s nothing like you! She’s a rapper from Queens!’ I’m a classical pianist,” Wang laughs — she also never experienced this particular breakdown. It was only while writing the script that Wang came to realize how long she had harbored these feelings, which she now refers to as “a very therapy moment.” The sorrow she felt during her trip to Changchun had to do with more than the idea of losing Nai Nai. The trip also served as a reminder of the life in China she had parted with.

Perhaps for this reason, Wang says, the most emotional scene to film was the farewell itself. Billi sits with her parents in the back seat of a taxi, watching Nai Nai and Nai Nai’s younger sister (played by Wang’s actual great-aunt) get smaller and smaller. Wang notes that filmmakers generally stray from using silence in movies — even if a setting is quiet, there’s still room tone, air conditioning, car sounds — but as the taxi pulls away from Nai Nai, the film dips into total silence.

“It’s almost like the air gets sucked out of the room, when it goes silent like that,” Wang said. “Everyone in the audience gets completely silent. And I feel it. It feels so heavy on my heart.”

“The Farewell” is now playing in theaters nationwide.