For Lucy Liu, “Rosemead” is a movie she had to make.

As star and producer, Liu, 57, spent years raising the money necessary to tell this tragic, true story about a mother and her only son.

It began with a 2017 LA Times article about a dying mother’s desperate measures to assist her troubled son. Liu read the screenplay two years later. “The fact that it is a true story was devastating,” she said in a Zoom interview.

“Then it took many, many years to get the 16 different investors that believed in this movie, who knew there was a universal message behind it.

“For me, this was special not just because I was a producer but because it’s a story that needs to be told, something that I really relate to because of not just the language, but the culture itself.”

Rosemead is a predominantly Asian community in California’s San Gabriel Valley where Liu’s Irene, an immigrant from Taipei, has settled. That’s why some dialogue is in Mandarin Chinese and subtitled

Irene is newly widowed; her husband died of cancer a year earlier. She too is terminally ill with cancer, while her high school senior son Joe (Lawrence Shou, a winning film debut) is diagnosed as schizophrenic.

We see the sad results when Joe decides to stop taking his schizophrenia medication.

“When he started to have an episode, things started to slide. He was under a great deal of pressure,” Liu learned. “He didn’t have enough support for him to really overcome that moment.

“And because she wasn’t fully aware of what was going on, she started to create her own narrative based on what she saw and witnessed. But she wasn’t really in touch with the doctor as much as she could have been.”

Irene, overwhelmed, joins her son’s therapy sessions, consults doctors and seeks help in traditional Chinese medicine at the local dispensary.

“The pressure of both parents being stricken by cancer and the fact that mental health and mental illness does run in the family, it probably triggered the diagnosis,” Liu said. “And when we start the movie, they’re still coming from a place of loss.”

Looking at Irene and Joe’s tragic, desperate conclusion means, “There’s so much that could have been done differently, that could have changed the events that occurred.

“This is about the love between a mother and her son, and the length that they’ll go to, to protect each other.

“But also within that time,” Liu stressed, “we see the lack of communication that happens because of it. With the unfortunate result of they’re not really connecting on a real level.”

“Rosemead” is now in theaters.

Lucy Liu stars in “Rosemead.” (Photo Vertical)