One of the biggest mysteries in It’s Okay to Not Be Okay is who Ko Mun-yeong’s mother is and what happened to her. From what we know earlier in the series, her mother mysteriously disappeared and was presumed dead.
In the first episode, Mun-yeong calls herself an orphan, but Nam Ju-ri tells her that her mother is still alive. Mun-yeong responds that she registered her death a long time ago, but her soul is still alive.
One time, a patient at OK Psychiatric Hospital thought that Ko Mun-yeong was her daughter. And for a while, Mun-yeong thought she was her mother. Another patient also pretended to be her mother.
In the latter part of the series, we finally get our answers about Ko Mun-yeong’s mother. The truth about her mother is definitely one of the show’s biggest revelations.
Warning: This article contains spoilers for It’s Okay to Not Be Okay. Read at your own risk!
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Who Is Ko Mun-yeong’s Mother and What Happened to Her?
Ko Mun-yeong’s mother, Do Hui-jae, is actually Park Haeng-ja, the head nurse of OK Psychiatric Hospital.
Years ago, Do Hui-jae killed Choi Hee-jin, her housekeeper who happens to be Gang-tae and Sang-tae’s mother. Ko Mun-yeong’s father, Ko Dae-hwan, found out about this and was terrified.
Mr. Ko had a brain tumor, and he did not want his daughter to become a monster like her mother when he died. Hui-jae/Haeng-ja laughs, so Mr. Ko pushes her over the railing.
Mr. Ko believes he killed his wife, so he hides her body in the basement. Later on, we see the body inside a suitcase, dumped in a lake.
But it turns out, Hui-jae didn’t really die. In fact, she’s been watching them all along with a new face and name.
It turns out, she was the reason why one patient killed himself. She was also the one who instructed patient Park Ok-ran to pretend she was Ko Mun-yeong’s mother. She was also behind the death of her husband later in the series.
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Why Did Ko Mun-yeong’s Mother Kill Gang-tae and Sang-tae’s Mother?
From what we know from the start, Choi Hee-jin, Gang-tae and Sang-tae’s mother was killed when they were younger. Sang-tae, the autistic brother, was the only one who witnessed the murder.
Unfortunately, due to his condition and because he was in shock, he couldn’t recall the details of the murder. All he remembers is that a “butterfly” killed his mother.
Since then, Sang-tae has developed a fear of butterflies, and he and his brother have been moving from one town to another to “run away from the butterflies.”
Later on, someone paints a butterfly in Sang-tae’s mural. The butterfly painted resembles the one-of-a-kind butterfly brooch designed by Do Hui-jae herself. This is when Ko Mun-yeong finds out that it was her mother who killed the mother of the love of her life.
It turns out, Do Hui-jae/Park Haeng-ja killed Choi Hee-jin because she got angry when the latter thought that something was wrong with Ko Mun-yeong.
Hui-jae wanted to raise a perfect daughter, and she was emotionally abusive to her. One day, Hee-jin finds Mun-yeong outside the “Cursed Castle”.
Mun-yeong looks at a bird with a broken wing and tells Hee-jin that maybe she should just kill it because it can’t fly anyway. This concerns Hee-jin, so she tells Hui-jae about this and that there’s a hospital her son goes to.
This results in Hui-jae killing her, as she thinks that Hee-jin is talking as if Mun-yeong is a lunatic. She also justifies the murder by saying that her housekeeper should not have crossed the line.
Hui-jae killed Hee-jin for a very small reason, which left Gang-tae frustrated, but he, Sang-tae, and Mun-yeong got justice in the end.
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What Happens to Ko Mun-yeong’s Mother at the Ending of It’s Okay to Not Be Okay?
Ko Mun-yeong’s mother goes to jail for her crimes. After she kidnaps Sang-tae, injures Gang-tae, and attempts to stab her own daughter, the police arrive, thanks to Director Oh Ji-wang.
Haeng-ja thinks she won because her daughter and Gang-tae cannot be together due to their mothers’ past. She says that humans are too weak, that’s why they suffer.
However, Director Oh responds that people stick together because they are weak. People lean on each other, and that’s what makes us human. He then asks if Haeng-ja will ever be human, but she doesn’t respond.
In the finale, Mun-yeong visits her mother and tells her that she pities her. Mun-yeong knows about warmth, while her mother isn’t even interested in knowing such. As she leaves, Mun-yeong tells her mother that she will erase her from her memory.
But Haeng-ja screams that that will never be possible because they are both the same. Mun-yeong then responds that a butterfly symbolizes a cure and leaves for good.
We last see the villain of It’s Okay to Not Be Okay slamming what’s in front of her, while Mun-yeong, Gang-tae, and Sang-tae get their happy ending.
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