In a big city in China, sister Kelly and Molly Lin go through their everyday routine,
unaware that their mother Mrs. Lin has hidden cameras in the house to keep an eye on them
at all times. Mrs. Lin is a very strict woman, picking up after their daughters seconds after
they finish eating even a snack, and pressuring them into doing well at school for the sake of the
future. One evening, Molly is studying when the stress and the pressure finally become too much,
so she goes to the balcony to end things for herself while her sister is still in the room.
Losing her daughter is devastating for Mrs. Lin, who can't stop having nightmares about Molly's
death and gets distracted by intrusive thoughts that sometimes keep her away from housework.
However she doesn't stop being strict towards Kelly, in fact now Kelly is the only target
of her mother's emotional outbursts. When Kelly brings her report card and her mom learns she's
failed three classes, Mrs. Lin scolds her as she wonders why she can't be more like Molly and makes
her kneel on the floor until dinner is ready. Mr. Lin, who happens to be the Dean at Kelly's school,
is also starting to get tired of Mrs. Lin's mood; he's as supportive as he can but Mrs.
Lin won't talk about anything else except Molly and makes every meal miserable. Mrs. Lin feels
guilty for not having seen the signs that made her daughter take such a decision, and Mr. Lin tries
to remind her is too late to play a guessing game now because Molly can't go back, but his words are
ignored. Desperate for answers, Mrs. Lin starts searching her daughters' room and is shocked to
find hidden papers that indicate Molly had been taking medicine for depression. Thinking back,
she remembers Molly's last day, when she proudly told her she got the highest score
in essay writing, but instead of congratulating her, Mrs. Lin scolded her. She reminded her
that the subject that matters is math because Molly had to go to medical school, so instead
of wasting time writing she had to practice more math problems, offering her own help since she has
a master's degree from the States. Mrs. Lin also wanted Mr. Lin to be part of the conversation,
but he kept staring at his phone. Mr. Lin thought he deserved a break after being at work all day,
but Mrs. Lin scolded him anyway, saying he only works eight hours while a housewife works 24/7
yet she never asked for a break because she had to save face. Tired of her rants,
Kelly and Mr. Lin left the table, prompting Mrs. Lin to comment she was the only one with
self-awareness in the family. Back to the present, Kelly is taking extra classes with a tutor,
who Mrs. Lin approaches at the end of the day to ask her to give Kelly what used to be Molly's slot
too. The tutor is unsure about this because double the slots would be too much for Kelly, and when
Mrs. Lin swears her daughter needs it, Kelly cries out she doesn't want to and runs to her room. As
soon as the tutor is gone, Mrs. Lin goes after Kelly to yell at her, calling her useless and
accusing her of wasting her parents' money. She reminds Kelly she could've been a professor too if
she hadn't become a mother, and Kelly snaps back, telling her she never asked to be born. Offended,
Mrs. Lin stomps out of the room, leaving Kelly to have a breakdown on her own. Later,
Mrs. Lin wonders if it had been a mistake to drop her career and depend on Molly for the future. She
also tells her husband she went to school to pick up Molly's things and found a bunch of novels plus
some letters for a boy called Sheng-Yao thanking him for his support. She didn't know about any of
these things, and Mrs. Lin feels like she didn't know her daughter, she also points out that Molly
was very smart and she couldn't understand how she could do something so incredibly stupid. As
Mrs. Lin wonders if she had been too careless, Mr. Lin interrupts her and tells the opposite:
she had cared too much. This triggers another rant from Mrs. Lin, who hates her husband's
implications of her being a control freak because everything she does is for the family's own good.
An argument begins between husband and wife which can be heard by Kelly from her room,
keeping her from sleeping. At that moment, Kelly begins remembering another bad night she had a
few weeks ago. Molly had been up studying until late, and Kelly could hear her sniffing, but Molly
pretended it was allergies instead of crying. Molly also started wondering why she had to study
so much since at first she thought studying could get her what she wanted but obviously it isn't
the case after all. When Kelly mentions Molly already has everything and everyone likes her,
Molly drops the subject and accepts to go to bed while cuddling her sister for comfort. The next
day at school, Kelly is having the usual nap teens have in lunch break, but she's interrupted by a
teacher that drags her to a study room. Molly used to come here on her breaks to study more,
and Mrs. Lin has sent orders that she wants Kelly to do the same. In this room, there's a
locker that still has Molly's name, and when Kelly opens it, she finds some shocking papers that she
decides to bring with her. Meanwhile Mrs. Lin has discovered that Molly was seeing a psychologist
behind her back and goes to pay her a visit. Doctor Zhao refuses to share any information
about Molly's mental state because that's private patient information, causing Mrs. Lin to call her
a bad doctor and leave in a huff. Afterward, Mrs. Lin goes home to search Molly's things
again and suddenly remembers a lunch she had with another family a few months ago, where she told
everyone about Molly's amazing achievements and how she would be a great doctor someday,
which annoyed Molly a lot. Mrs. Lin's friend had a son named Zhi-Xiong, who told everyone about his
latest research: he was working on a machine that would observe a person's daily routine,
and based on that, it could accurately guess that person's thoughts and behavior. This would allow
him to get actual memories that maybe not even that person wanted to face. Back to the present,
Mrs. Lin goes to see Zhi-Xiong, who explains the machine is still in the trial phase because they
have no human subjects to try it on, and nobody wants to volunteer because they would have to
share many private things. Mrs. Lin wants him to use this machine on Molly to find out why she
did something so drastic and hands him a USB stick with all the recordings from her security cameras.
Now Zhi-Xiong only needs a few days to create a model based on all this data. When Zhi-Xiong
contacts Mrs. Lin again sometime later, he has bad news: the information on the USB stick isn't
enough. This only shows Molly's home life, which Mrs. Lin already knew about, to fully understand
her they need her other memories. Desperate for answers, Mrs. Lin gives Zhi-Xiong permission to
access Molly's body and put a chip in her brain to gain access to her neural activity. The procedure
goes smoothly, but the idea of reactivating Molly's neurons even if temporarily won't
stop bothering Mrs. Lin, who keeps imagining Molly waking up and finding herself trapped inside the
coffin. Later during dinner, Kelly says she's going out instead of studying because a tutor
can't magically make her smart like Molly. Mr. Lin worries about her, but Mrs. Lin tells her
she can do whatever she wants and leaves the table after announcing she's tired of dealing with her.
The next day, a stranger leaves an envelope for Mrs. Lin containing a mysterious news clip. When
Zhi-Xiong is finally done with the recreation of Molly's mind, he connects the machine to Mrs. Lin,
who chooses to first visit Molly's last day. The poor girl had felt horrible over dinner when her
mother wouldn't congratulate her on the essay achievement, and later while she was studying,
she kept hearing her sister laughing at some comic she was reading behind her school book. Feeling
alone and hopeless, Molly couldn't take it anymore and moved to end it all. When the memory is over,
Mrs. Lin remembers the news clip someone left at her house, which was about a short story contest
won by Sheng-Yao, the guy in Molly's letters. Still in denial, Mrs. Lin thinks he may be
responsible for Molly's death and asks Zhi-Xiong to let her access older memories, not caring
about the warning on how living through Molly's depression may affect her own mood. The next
memory she visits shows her the time Sheng-Yao took Molly to a book signing event, where Molly
got to meet her favorite author and share the fact she wrote as well. This author accepted to look
at Molly's short story for the contest after the event was over, but in the middle of it,
Molly got messages from Mrs. Lin demanding that she come home immediately. In the end, Molly never
showed her story to the writer or sent it to the contest, and she left the event in tears. This
incident makes Mrs. Lin more sure that Sheng-Yao is to blame for Molly's deviance and decides to
drop by the school to talk to him. Sheng-Yao explains he likes boys and he was never in a
relationship with Molly, he had just been a friend who wanted to support her dreams. He doesn't have
her novel because Molly was very protective of her work, and this makes Mrs. Lin think she wrote
something shameful. Such a statement finally makes Sheng-Yao snap and he tells Mrs. Lin that he felt
pity for Molly because lots of people knew she had a beautiful talent that her mother wouldn't
let her pursue. Mrs. Lin refuses to believe "lots of people" knew about this side of her daughter
and she didn't, so she assumes she must've been a bad writer and that's why she ended things. Later,
Mrs. Lin admits Sheng-Yao was right about one thing: she didn't know Molly well. But at the
same time, if she hadn't been such a controlling mother, she wouldn't have found out all this extra
information. The next time Kelly comes home with bad grades, Mrs. Lin is so furious she almost hits
her with the duster, but she stops herself just in time because she hallucinates Molly being there to
stop her. Sometime later, Mrs. Lin goes to see Dr. Zhao again, this time asking to become her
patient. She explains she's been losing control of her emotions and she's had trouble sleeping,
so she worries it may be depression. Dr. Zhao thinks it's too soon to tell since it may also be
the grief that isn't being dealt with, prompting Mrs. Lin to confess she's been watching Molly's
memories. One of these memories had been of Molly stealing a hairpin and bringing it home as a gift
to her mother, who had scolded her for wasting money. Mrs. Lin has come to understand she didn't
know her daughter at all, but she isn't sure if looking at the memories is making her feel
better or worse. Dr. Zhao wonders why Mrs. Lin won't respect her daughter and if she saw all
the memories why she's still come to her for help, by now she should already understand what happened
and why Molly lied and hid things from her. Mrs. Lin doesn't get it and keeps asking for help,
so Dr. Zhao gives her an exercise to deal with her denial: she must put herself in Molly's point of
view and understand how Molly saw her own mother. As she explains this, Dr. Zhao remembers one of
her own meetings with Molly, where she admitted she felt like a deviant because stealing and
watching her mother wear the stolen goods made her feel guilty yet good. It started in sixth
grade when she only took some money from Mrs. Lin and got hit for it, and since then stealing
became very appealing to her. She didn't know if she wanted to look for pain or avoid pain,
and every time she didn't do well on her exams, she added a mark. Dr. Zhao thinks Molly did that
to take punishment, prompting Molly to confess she kept dreaming about Mrs. Lin finding the scars one
day and apologizing for everything. Molly included all these things in her stories, which made her
hurt more because she was exposing her emotional wounds. Dr. Zhao had told Molly to believe in
her own talent and to share the novel with her family to see what happened, but Molly never
dared. It's then revealed that the papers that Kelly found in the study room are Molly's story,
which made her cry her heart out when she read it. Keeping Dr. Zhao's exercise in mind, Mrs. Lin goes
to see Zhi-Xiong again and asks to see herself from Molly's point of view. Finally Mrs. Lin
gets to experience what an authoritarian mother she had been: even when Molly had been a small
child and was saying silly things like wanting to be a cashier someday, Mrs. Lin would correct
her to say "accountant". Whenever she talked to her friends, Mrs. Lin would say having children
was an investment; when Molly was in first grade learning the basics she was already pushed into
studying more, Mrs. Lin would act cold towards any gifts Molly made for her and whenever Molly came
home with good grades, instead of congratulating her, Mrs. Lin told her it was thanks to her mother
keeping an eye on her studies and not to be too pleased with herself or she'd lose rank.
Whenever Molly made a mistake, Mrs. Lin yelled at her; whenever Molly asked for even a little cash,
Mrs. Lin would scold her for wasting money and demand gratitude. All of Molly's memories
of her mother were like that: Mrs. Lin yelling at her, pressuring her,
deciding her future, calling her interests a waste of time, calling her an embarrassment,
and threatening with hitting her if she didn't study. Overwhelmed by finally seeing the truth,
Mrs. Lin removes the device from her head and finally admits it's her fault Molly is dead.
She goes to see a cop and asks to be arrested, but this isn't something the police can cover, so they
call Mr. Lin to ask him to pick up his wife. The next day, Kelly gives Molly's story to her mother,
and Mrs. Lin gets to read the letter she wrote for the judges, saying her hard life didn't train her
to write yet it's also what inspired her to do so, putting her painful memories on paper was
Molly's hope to inspire and help others like her, but she also hoped her family didn't read this,
especially her mom, this is why Sheng-Yao entered her story in the contest under his name and won.
After crying for many hours, Mrs. Lin sneaks into Zhi-Xiong's lab without his permission
and turns on the machine to experience Molly's last day again. Her brain finally snaps under
all the pressure of Molly's depression, making her remember Molly's birth at the same time she
experiences Molly's last day under full pain. When Mrs. Lin opens her eyes again, she hallucinates
Molly being there with her again, and she hugs the air as if that could truly comfort her.