“She understands the culture of this area and this time to the core,” says Baker. “There were so many conversations that we didn't have to have because [that] deep understanding.”

Baker has portrayed New England life on stage before, but this is the first time the 43-year-old playwright – who won a Pulitzer Prize in 2014 for “The Flick,” about low-wage workers in a movie theater – has written and directed a film. The recent coming-of-age drama “Janet Planet” is understated; Baker highlights the simple joys and existential conundrums of everyday life. “Her characters struggle with longings and the need to prove their worth, but they rarely voice their struggles out loud,” reads the Washington Post's four-star review.

Fortunately, Nicholson, 52, is known for conveying big emotions without fuss. Her characters' restraint could be mistaken for stoicism, but look closer and you'll see a swirl of emotions simmering beneath the surface. Her furrowed brow speaks volumes. That ability earned her a 2021 Emmy Award for the HBO crime thriller “Mare of Easttown,” in which she portrays a small-town woman who learns excruciating truths about her family, and caught Baker's attention in the 2019 film “Monos,” in which Nicholson plays an engineer held hostage by teenage guerrillas in a Colombian jungle.

According to Baker, Nicholson is an “unremarkable actor.”

“She's always thinking and you can see it in her face, but what exactly she's thinking is hard to express,” says Baker. “That kind of active thinking combined with psychological mystery seemed really, really important to the role. It's a very rare quality that she has in abundance.”

“Janet Planet” is set from the perspective of 11-year-old Lacy (Zoe Ziegler), a quiet, thoughtful child who lives with her single mother, an acupuncturist. In the summer of 1991, Janet receives three visitors whose visit reveals to Lacy that Janet may not be the woman she thought she was. Press materials describe this gradual disillusionment as “falling out of love with your mother,” a phrase that makes Baker cringe today. “I feel like it's more complicated than that,” she says.

Once again, Nicholson gets it. Lacy sees Janet not only as her diligent caregiver, but also as a full human being with her own needs. The actress recalled moments from her childhood to better relate to the story, recalling the “long hugs” that some of her mother's friends, an herbalist, would share. The extended hugs left Nicholson squirming at the time. It was hard to understand why these adults, who were supposed to have everything under control, were clinging to each other.

“You could feel the distress or desperation in one or both people,” she says.

After some reflection, Nicholson believes that her mother's friends, who led more unconventional lifestyles, were “searching for meaning.” In the film, it is Lacy who makes this discovery. She silently watches as Janet hugs her old friend Regina (Sophie Okonedo), with whom she has been estranged since a fight years ago. Lacy becomes protective of Janet when her boyfriend Wayne (Will Patton) freaks out about his mental health issues. Later, Lacy curiously watches Janet chat with Avi (Elias Koteas), the leader of a cult theater troupe who has his eye on her.

Sometimes Janet shares her thoughts with Lacy. When Wayne's seizures begin, Janet asks the teenager what she should do. Recalling the short time before her own mother remarried, Nicholson says that single mothers and daughters have “a very special relationship.” There can be a certain level of codependency, she explains, “and I don't mean that in a negative way. It's just different.”

Baker, who grew up with a divorced mother, adds that “marriage gets a lot of gray area exposure without too much moralizing. I felt like I hadn't seen that in a parent-child relationship the way I wanted to.”

Over the course of the summer, Janet and Lacy grow together. Lacy, who struggles to make friends her own age, tries to understand human relationships. Her journey is about “how a child's perception, worldview, philosophy and spiritual life can change in two months, which is a huge amount of time for an 11-year-old girl,” Baker says. Janet learns that she must seek validation from within, not from men like Wayne and Avi.

“That's a big key to her personality and where she's received great recognition for most of her life,” says Nicholson. “She's always been able to rely on that kind of attention.”

Baker says she has written several screenplays throughout her career, but chose “Janet Planet” as her directorial debut because “it was the first time I wrote a script that I could really see.” While the story deals with universal themes, its covers are region-specific. Baker returned to Western Massachusetts while writing, spending a month among other artists in the foothills of the Berkshires. She sneaked onto the grounds of her old Shire Village summer camp in Cummington — where they shot the opening scenes of “Janet Planet” — and soaked up the natural sounds of summer in Amherst. The film eschews a traditional instrumental score so as not to “undermine the power of the bugs and trees,” she says. “I didn’t want to foreshadow at all what was happening inside [Lacy’s] Brain through music.”

Working on the film brought back a flood of memories for Nicholson, who hadn't been to the area for about 30 years. “It's crazy how much of it is unchanged,” she says. They shot a scene in the Hampshire Mall in Hadley, which still houses the JC Penney that is so important to her. On the way to another location, they drove through Goshen, where Nicholson worked as a camp counselor every summer. She took her family members and showed her two teenagers the street she grew up on. She visited old swimming holes with her mother, now 73.

Much of the filmmaking process, says Nicholson, was about “deepening our connection to the place, as it plays such an important role in the film.” Entering Janet's life – in such a personal setting – caused the actress to reflect on what it means to examine where you come from. Was she revisiting the past or creating a new present? Whose inner life was she exploring?

“Is it me? Is it my mother? Is it my mother's friends? Women in general? Middle age?” she says. “You have to look a little deep into your own heart to find out. But for me, that's the exciting part.”