The 2025 Taiwanese thriller drama series on Netflix, Had I Not Seen the Sun, opens with the premise of a crime mystery thriller, as a documentary crew visits a notorious serial killer in prison nine years after his crimes to learn more about him, and particularly his motive behind the murders. But it soon throws in significant helpings of teenage romantic drama, giving the show the shape of your typical high-school romance, as butterflies flutter around and love ballads blare in the background whenever the central characters come close to each other. With the show released over two parts, Had I Not Seen the Sun part 1 mostly sets up the context and the backstory to the characters but also leaves with an unexpected twist at the end, setting up for the release of part 2 in December of 2025.
Spoiler Alert
What is the show about?
Had I Not Seen the Sun part 1 begins with a chilling scene from 2014, in which a man wearing a hooded jacket enters a roadside eatery and places an order with the owner. But just minutes later, as the man eats his dinner without a care in the world, the restaurant owner is seen lying in a pool of blood, clearly having been stabbed multiple times by the stranger. In a short collection of news briefings and headlines, the gruesome details of 4 more murders are revealed next, all having been committed by the same man, termed the Rainstorm Killer by the police. Within just a few months, a man named Li Jen-yao is arrested on suspicion of being the notorious serial killer after he turns himself in at a police station, stating that he has murdered his father and also all the previous individuals. The 25-year-old man is quickly sentenced to life imprisonment and held at a super-security prison, as he had confessed to his crimes himself, but he never reveals his motive behind the violent murders.
Jumping forward to 2023, a documentary film production company plans on shooting a film about Li Jen-yao and his crimes, as the shroud of mystery over why he had committed the murders has still not been lifted in these 9 long years. Jen-yao has refused to tell his story or perspective to journalists and filmmakers for all this time, but has now strangely accepted the offer made by this particular company, much to the excitement of its owners, Hsu Ta-wei and Chien-yi, with the former overseeing this project. It is the company’s junior employee and PA, Chou Pin-yu, who had approached Jen-yao, and it seems very likely it is only because of her that he has agreed to talk. This is all the more evident when Jen-yao stares at Pin-yu with a feeling of familiarity and affection, which gets to her as well, as she soon starts to have strange but romantic dreams about the serial killer.
What is even more strange is that Pin-yu starts seeing the ghost, or apparition, of a young woman at her new apartment, where she moved in only two weeks ago. Her neighbors warn her that the apartment is notorious for being haunted by the ghost of an earlier tenant, a woman who had died mysteriously in the mountains. A fruit-seller couple then approaches her and gifts her some of their fruits as if they have an old connection with her, but Pin-yu is totally confused about all this. She shares the matter with her close friend, Mu Shen, but cannot find any meaning behind her supposed hallucinations before the very ghost one day lets her connect with her memory, and Pin-yu witnesses a story of love, betrayal, and sheer brutality.
Why did Jen-yao’s childhood push him towards criminal tendencies?
One of the most crucial matters uncovered over the long duration (we spend more time in the past than in the present) the plot spends in 2007 is Li Jen-yao’s unusual experiences as a teenager, which directly pushed him towards criminal tendencies. From a very young age, Jen-yao was subjected to domestic abuse, as his alcoholic and wastrel father would regularly assault his mother in front of him and sometimes beat up the boy as well. The man also owed a lot of money to a local gangster named Big K, because of which the goons would often harass Jen-yao and his mother on the streets and even come to their house to create trouble. As a teenager, Jen-yao was very directly and constantly told by his father that he was not wanted in the house and that he was only a burden, making the boy feel extremely lonely and helpless in life.
There were moments when he tried resisting by picking a fight with his father, but his mother would intervene, as she was of a docile nature, and she believed that no son should get into physical altercations with their father, no matter what. She was so accustomed to the horrific abuse and humiliation that she had stopped questioning the actions of her husband and would ultimately end up siding with him every time, clearly out of fear. When Jen-yao frustratedly led the gangsters to his father on one occasion, he hoped and expected his mother to support him and so was left shocked when he realized that she had decided to go away to Taipei with her husband so he could evade the gangsters, abandoning Jen-yao in the process.
All these painful experiences had turned Jen-yao into a loner who would spend his days at school sticking to himself, and the extremely unhealthy environment back at home had affected his academic and disciplinary records as well, making him unpopular among the teachers at the strict military school. Although his classmate, Hsiao-tung, showed genuine concern and then a strong bond of friendship towards him, Jen-yao initially turned her away rudely. But he had to give in to his romantic feelings for Hsiao-tung eventually, as she too expressed an emotional connection with him, and soon she became his only ray of hope. While his parents did return home after some time, having made enough money in Taipei to pay off their loans, Jen-yao could never really trust them anymore, although what followed was still very shocking for him.
Instructed by his boss for some related reasons (discussed later on), Big K approached Jen-yao’s father after some time and reminded him how gangsters in Taipei were now looking for him, since the man had acquired the money by illegal and shady means. Big K agreed to take up the responsibility of paying back the amount to the goons from Taipei, but in exchange, he wanted him to frame his own son for drug possession. Without even a second of hesitation, the man agreed to the deal for a mere half a million Taiwanese dollars and planted drugs among Jen-yao’s possessions before two police officers searched his belongings and found them. Li Jen-yao had to run from the police, and he already became a fugitive in his teenage years,leaving him inclined towards criminal activities. There was hardly any doubt that he would resort to violent means, especially in order to avenge his beloved Hsiao-tung.
What is Mu Shen’s real identity?
Mu Shen is initially introduced as Chou Pin-yu’s close friend, and possibly her cousin, as she might have truthfully told the police officer at the metro station towards the beginning of the series. However, as we delve deeper into the past, it becomes evident that Mu Shen had a connection with the serial killer Li Jen-yao through the latter’s girlfriend, Hsiao-tung. Mu Shen was known as Yun-chen in 2007, and she was Jen-yao’s classmate at the military school in Taichung, where she also became best friends with Hsiao-tung. Yu-chen also had a sad secret—her mother had abandoned her after her father’s death, and the little girl was stuck with her affluent but extremely controlling grandmother. The grandmother was cruel, manipulative, and even abusive towards the young girl, as she wanted to raise Yu-chen by her ideals and, most importantly, wanted her to not be like her disgraceful mother. To this end, she would often physically and emotionally torture the girl.
Yu-chen sought respite from the struggles at home in a new friendship that she struck up with Hsiao-tung, who was an exceptionally gifted ballet trainee. With time, she also realized her romantic interests in women and soon became emotionally attached to Hsiao-tung, although she could never admit her feelings to her best friend. Therefore, when Jen-yao grew close to Hsiao-tung, Yu-chen was visibly disturbed, and she made numerous attempts to wedge a gap between them before eventually accepting defeat in love. In this while, Hsiao-tung had helped her escape her evil grandmother, especially after Yu-chen had accidentally struck the old woman and left home, wrongly believing that she had died. Ultimately, she was able to reunite with her mother in Taipei and went on to stay with her under a new identity as Mu Shen.
Although Mu Shen is portrayed as an extremely supportive and helpful friend to Pin-yu in the present, she also has her fair share of secrets. To begin with, she completely hides her connection to Jen-yao from her friend, and she even visits the jail to confront the serial killer right after he starts opening up to the documentary team. Mu Shen does not want Jen-yao to reveal his motive, and following her visit, he refuses to talk to the filmmakers anymore. There is clearly something more to Mu Shen’s story, which will only be revealed in Had I Not Seen the Sun part 2, and it would not be surprising if she is revealed to have been more intimately linked to the murders even, since she too loved Hsiao-tung and would have done anything to avenge her.
Why did Ouyang Ti target Jen-yao?
Ouyang Ti, the despicable son of a corrupt politician in Taichung, becomes the main antagonist in Had I Not Seen the Sun part 1, as his vile acts from 2007 are revealed. Ever since laying his eyes on Hsiao-tung, Ouyang Ti wanted to be with her, not really out of any genuine sense of love, but more so to own her like a prize. Because of his family’s habit of always buying their way into every privilege, Ouyang was frustrated by Hsiao-tung’s repeated rejections, and he kept thinking of ways to convince her. This was when he spotted her and Jen-yao together and realized that the two were growing close to one another, which frustrated him even more. But Ouyang did not react like any usual jealous teenager, and instead chose to take a predatory and much more vile approach to the whole situation, taking an oath to completely ruin the lives of the two lovers, simply because Hsiao-tung had rejected him.
His anger and respite now found a new target in Jen-yao, and he started to take perverse pleasure in insulting and causing harm to the boy. A shameless pride in his family’s wealth and influence and outright spite for those less privileged worked in Ouyang’s repeated attempts to humiliate Jen-yao. As he befriended another girl from school, who saw Hsiao-tung as a rival in ballet class, they came together to take action against the couple. The girl filed a complaint about the two getting intimate on the roof, although she mentioned only Jen-yao’s name, stating that she could not see who he was with. The fact that Jen-yao only hung out with Hsiao-tung made them feel confident that the latter would get punished. This was when Yu-chen had jumped in to save her beloved Hsiao-tung and had instead taken the blame upon herself, stating that it was she who had been with Jen-yao. Ouyang then had drugs planted on Jen-yao, through the gangster Big K, who actually worked for his politician father, just to mess around with the boy. But as his attempts mostly failed, Ouyang Ti eventually came up with the most horrific plan to hurt the couple and leave them traumatized for life.
What led to Jen-yao and Hsiao-tung’s painful separation?
When Ouyang had Jen-yao wrongfully marked as a drug dealer, the only reason that the latter could not approach the authorities with the truth was a certain photograph of him that Ouyang had taken. Some time earlier, Ouyang had instructed Big K to inject Jen-yao with a drug, and as the boy lay in a trance, he took a photograph of him, which clearly showed Jen-yao to be high. Now, Ouyang threatened to show the police this photo as solid proof of him being a junkie, which would completely ruin his life once and for all. When Jen-yao shares all of this with Hsiao-tung, she secretly makes a plan to feign interest in Ouyang and give in to his advances temporarily, only so that she can delete the incriminating photo from his phone.
Thus, she asks Ouyang to take her out on a date at a karaoke bar, and despite suspecting her intentions in doing so, he agrees to the date. By the time this particular night comes, Hsiao-tung learns that Jen-yao has been able to get in touch with a lawyer who has assured him that even the photo cannot be used to do much harm to him, but it is still too late for her to cancel her date. Just to take an extra step to ensure her beloved boyfriend’s safety, Hsiao-tung attempts to delete the photo from Ouyang’s phone but gets caught in the act. Ouyang and his friends then mercilessly force themselves upon her in a drunken state and even make a video of it, which they upload on the internet a few months later.
Despite all the efforts that Hsiao-tung’s parents take to do their daughter justice by filing official complaints, they are ultimately quashed, clearly because of the influence of Ouyang’s family. The police tell them to sort the matter out with the school authorities instead of making it a legal issue, while the school authorities side with the politician’s family and choose to believe that it was Hsiao-tung and her family who were trying to defame Ouyang and his friends. Ultimately, the girl is almost forced to take the decision to go away from Taichung, as she and her family move to Taipei in order to get away from the trauma and shame of the sexual assault, upending her life and her potential career in ballet. This finally led to Jen-yao and Hsiao-tung’s painful separation as well, although they promised to meet once again in five years’ time.
Who did Jen-yao run into in 2014?
Once Hsiao-tung and her family had left Taichung, there remained no reason for Jen-yao to hold on to the stability in his life, as he could not find any purpose in everyday life anymore. He was consumed by a drowning sense of vengeance and wrath, which soon made him calmly return to the school one day, despite having been expelled earlier, and stab Ouyang Ti without making any fuss about it. Although Ouyang survived the attack, Jen-yao was immediately arrested and sentenced to a few years in juvenile prison. Ouyang’s equally corrupt mother kept making all attempts to have Jen-yao’s juvenile sentence increased as much as possible, but he kept making just one frightful promise to her—that he would get out of jail one day and kill her son, along with all his friends who had a hand in the horrific crime against Hsiao-tung that night. As we know from the very beginning of the series, Jen-yao does eventually deliver on this promise, but how he does it, and if he had any accomplices along the way, would only become clear in the 2nd part.
Had I Not Seen the Sun part 1 ends with Jen-yao’s release from prison in 2014, after which he visits the military school in Taichung. Albeit many months late for the promised reunion between Hsiao-tung and him, he visits the school to realize that his estranged beloved had indeed come and waited for him at the spot, even having decorated the place to make Jen-yao experience the joy of Christmas. 8 more months later, he suddenly sees a black butterfly fluttering around on the street, as if pleading him to follow it. In their short but intense romantic relationship, Hsiao-tung had always represented a butterfly, giving hope of seeing the sun to Jen-yao, who was more like a moth, always engulfed in darkness.
Because of this connection, Jen-yao now follows the butterfly to come across a visually impaired woman who introduces herself as Hsia Tien-ching, and he helps her reach the radio channel office where she is about to host a show. Despite feeling heartbroken once again, as he had felt that the butterfly must have led him to his beloved Hsiao-tung, Jen-yao shows the woman genuine kindness, and this is when he notices the butterfly tattoo on her finger, exactly the same as Hsiao-tung had, and even on the same spot. The series leaves us at this very intriguing point, and both we and Jen-yao are left to wonder whether Tien-ching is indeed Hsiao-tung. Perhaps Hsiao-tung has gone through some severe experiences that have left her in this state, almost totally unrecognizable from her younger self. If Tien-ching is indeed not the girl from Jen-yao’s childhood, then she has some deep connection with Hsiao-tung at least, which will be revealed in the 2nd part of the show.
Is Pin-yu really haunted by a ghost?
Had I Not Seen the Sun part 1 ends up giving significantly less time to the present timeline, as the identity of Pin-yu still remains a mystery, and even more so the question of whether she is really being haunted by a ghost at her new apartment. Initially, it had seemed like she was the adult Hsiao-tung, based on how the girl’s parents seemed to recognize her and how her being ‘visited’ by the young girl could have been representative of her getting her old memory back. But with the ending of part 1, this seems less likely, and it might be that Pin-yu’s extensive research on the cases might be having an effect on her mental health, and she is hallucinating the ghost of Hsiao-tung. The last possibility is that the supernatural does exist in the world of Had I Not Seen the Sun, and the definite answer to this will be revealed only in the 2nd part of the series.
