‘Parasyte: The Grey’ Ending Explained & Series Summary: Do Su-In And Heidi Get Separated?


Parasyte: The Grey is a new South Korean science fiction thriller series streaming on Netflix that has been adapted from a Japanese manga series named Parasyte. The world presented in the show suddenly faces an unusual sort of invasion from an alien species, as some parasitic creatures silently make their way inside human bodies, taking over full control and planning to take over Earth as well. Amidst all this is a young woman who has to agree to a strange co-existence with the parasite in her body, for she cannot be taken over completely. Overall, Parasyte: The Grey is quite a nice and thrilling watch, although it is not necessarily the most convincing show of its kind.

Spoiler Alert

What is the series about?

Parasyte: The Grey begins with a man boasting about his bravery and readiness to kill people on an online forum, as he is clearly a lonesome individual not in the healthiest state of mind. In the next hour, the man leaves his house and goes over to the nearby grocery mart to pick up some items, and has a terrible row with the woman working as the cashier. The man had not followed the instructions mentioned about purchasing items at the store, and when the cashier pointed this out to him, he was infuriated. Already heated up by the bullying that he faced online, and also because he suffers from schizophrenia, the man decides to take revenge on the cashier for the humiliation. As the woman leaves the store at the end of her shift, the man starts to follow her in his car. On an empty stretch of road, he rams into her scooter and then goes on to stab her in the waist numerous times. The woman somehow crawls off into the bushes, struggling with the pain and the blood loss, when something very strange occurs. The violent man suddenly falls dead on the ground as if ripped apart by some sharp, invisible blades. 

When another car passes by the place and reports the incident, the woman is immediately admitted to the local hospital. She is introduced as Jeong Su-in, also a solitary person without any family since her very childhood after her mother abandoned the family and she had to report her own father because of his abusive habits. At present, Su-in’s survival is still a mystery to her and the police, especially because the stab wounds on her body are not fresh at all and seem to be just scars from a long time ago. The mutilated body of her attacker remained unexplained until some other incidents were discovered by the police. Around the same time as Su-in’s showdown with her attacker on the empty road, a bizarre scenario unfolded at a music festival in Korea, in which a human being was transformed into something monstrous, and it attacked and killed many of the performers and fans present at the scene.

Gradually, the premise of Parasyte: The Grey becomes clear, as it is revealed that a few hundred parasitic organisms from outer space had rained upon South Korea and various other parts of the world on that fateful evening. These organisms then entered the bodies of the nearest humans they could find and took over their brains, turning them into puppets. These parasites made use of their long tentacles to kill others and cause havoc, with the sole intention of taking over planet Earth. Su-in had been incidentally invaded by a similar parasite, but the effect on her was very different than on everyone else. Since the woman had already been injured by the time the parasite entered her body, and she was facing death from the stab wounds, the parasite had to focus on healing her body first, because of which it could not reach her brain and completely take over her body. As a result, Su-in exists normally at most times, while her parasitic self, later named Heidi, comes out whenever she is in danger. The parasite greatly depends on the body it is inside, as it would die if the body were dead, so Heidi is careful to use her powers and protect Su-in at all times. Su-in, meanwhile, has to cope with this unnatural co-existence while keeping herself and her friends out of trouble.

How do the parasites plan on taking over Earth?

After getting hold of human bodies, the parasites in Parasyte: The Grey make an elaborate plan to strive towards their ultimate goal, which is world dominance. While not much background about this invasive alien species or how they came to Earth all of a sudden is provided, the plan of world dominance is evidently not something very sudden. It is mentioned that the organisms were actually raised with proper training regarding how to take control over human bodies, and they had indeed come prepared before landing on the planet. This is why they can infiltrate human society with some ease and particularly know how to keep their presence and mission secret from the world. It is common knowledge, even among aliens, that human beings have many religious cults that authorities don’t meddle with and, hence, are safe spaces for various unusual and sometimes dangerous practices. Therefore, the first step of the parasites is to start a religious body named the Saejin Church, which is actually just a front for all of their kin to come together and form an organization.

Along with the main focus on taking control of human society, the alien parasites are also seemingly interested in understanding human minds and especially emotions, which are totally foreign to them. This is why there are instances of the parasites learning about human feelings and being amused by them. For the first few weeks, the plan goes on quite well as more parasites gather at the Saejin Church and discuss their next steps with regard to world dominance, all while hunting normal humans to be stored in a pantry as well. The human bodies in the pantry are either kept for consumption or to ensure that there would be enough extra bodies for the parasites if their current human bodies were damaged or lost in any way. The Saejin Church front is lost because of the personal investigation of Seol Kang-woo, a young man who is in search of his beloved younger sister. As Kang-woo eventually finds her sister’s body in the pantry, he decides to take down the parasites in a very personal revenge mission and drops an anonymous tip to the police about the church.

During this time, the lead investigator against the parasites, the leader of a special police task force named Team Grey, Choi Jun-kyung, had found a unique way to keep track of the parasites’ activities. Choi’s own husband had been affected by a parasite and had turned into a monstrosity, following which she trapped the man and captured him with a special mask. This mask ascertained that the parasite could not yield control over the human body, and Choi forced her husband to let her know about his new kin’s activities. The leader of the Saejin Church, Pastor Kwon, finally manages to have the captured parasite, named The Hunting Dog, killed so that the police can no longer track their movements with the help of the creatures’ ability to communicate through brain waves. Following this success, the parasites shift to a different abandoned shelter in Namil while planning for their next big hit. The mayor of the town is soon supposed to come to the neighborhood as part of his presidential campaign, and so the parasites want to take over his body and infiltrate the government.

Why is Won-seok working for the parasites?

Won-seok is a police officer and detective working in the Namil police station, and he is quite an experienced professional at a high post. Although there are superiors at the station, including the lead detective, Cheol-min, Won-seok is considered quite an important individual by most of the station. After the arrival of Choi Jun-kyung and her Team Grey, Won-seok makes a personal acquaintance with the woman, stating that he is a great fan of her detective work and would be obliged to help her mission in any way. However, Won-seok turns out to be a double agent, who is actually in an alliance with Pastor Kwon and the parasites, telling them all about the police force’s next steps and warning them before about planned attacks. It is also Won-seok who secretly murders the Hunting Dog, ensuring that Choi is left with no inside connection with the parasites, making her and the human side’s job immensely difficult.

Won-seok is, interestingly, the only human being who conspired against his species and became friends with the aliens, despite not getting invaded by any parasite. Whatever the man does is out of his own free will, and this makes it all the more confusing as to why he chooses to harm humans. But Won-seok is a perfect example of human betrayal for the sake of personal betterment, for he becomes an ally of the parasites only to ensure his own professional betterment, as the man intends to become a politician simply because of the associated money and power. When the invasion first took place, Won-seok was already a member of a local church, the leader of which was Pastor Kwon. After hearing that their beloved pastor had been seemingly sick and missing for a few days, Won-seok went to check on the man at his house, only to find that Pastor Kwon had been taken over by the parasite and had murdered his wife as well. 

The parasite then threatened to kill Won-seok, while also giving him the opportunity to be safe in exchange for working on behalf of them, and Won-seok readily agreed. The police officer never really regrets this decision, even directly asking for a role in the political scene. However, in the end, the evil leader parasite does not hesitate to kill Won-seok and take over his body, rendering all his service for them meaningless.

Why does Kyung-hee turn against the parasites?

When Seol Kang-woo returns home, he has to hide from a criminal gang after a failed assassination attempt puts his own life at risk. Kang-woo was part of the Mangnanis criminal gang, which had sent him to kill the leader of their rival gang, the Cheolis, but the young man failed to carry out this murder. As a result, the Cheolis were now after him, and Kang-woo had to run far from the place, returning to his family home in Namil and hiding in the neighborhood from his pursuers. However, as the plot progresses, Kang-woo learns that a grand betrayal had taken place against him, for it was his own gang members who were now looking for him. Seeing this as an opportunity to mend their relations with the rivals, the Mangnanis wanted to use Kang-woo as a mere pawn by delivering them to the Cheolis and letting them kill him.

While this level of betrayal is common among human beings, parasites are not used to such complexities at all until they, too, develop this very human trait. Kang-woo’s elder sister, Seol Kyung-hee, had been taken over by a parasite, and since then, she had been a very dedicated and selfless worker for their organization. However, as Pastor Kwon wanted to target the mayor, he needed the Team Grey force to be busy with a raid at a different location, which was planned to be at the second hideout of the parasites. Therefore, the leader ensured, through Won-seok, that this hideout would be raided by the police, who would also be content that all parasites in the area had been killed off and would not be prepared for the attack on the mayor. But because of this planned raid, many parasites, including Kyung-hee, would be sacrificed and killed. Kyung-hee finally realizes that her parasite leader has also become selfish and scheming like humans, and thus, she turns against them, making an alliance with Su-in and Kang-woo instead. 

Do Su-in and Heidi Finally get separated?

For the most part, Jeong Su-in had a very strong and loving supporter, the police detective Cheol-min, who was almost like a father figure to her. But towards the end, Cheol-min gets killed, and his body is taken over by the parasite that was earlier controlling Pastor Kwon. As a result, Cheol-min now also starts working against the police force, along with Won-seok, and at the end of Parasyte: The Grey, the parasites launch a serious attack on the mayor, intending to invade his body. However, Su-in and her parasitic alter-ego, Heidi, had also been ready for this attack, together with Kang-woo. They had been repeatedly trying to inform Choi Jun-kyung about the moles in the police force, but she was unwilling to listen.

In the end, Jun-kyung agrees to go over to the ceremony that the mayor is overseeing, but mostly because she is still pursuing Su-in, believing her to be a parasite. Although Heidi fights off Won-seok and protects the mayor, she is held at gunpoint by Jun-kyung. But Heidi does not fight back and instead kills a parasite that was about to enter Jun-kyung, and the task force leader shoots Won-seok dead. Heidi admits that having a sensitive and good-natured person, Su-in, as her host taught her a very positive human feeling of trust, and it was because of her decision to trust Jun-kyung that both the women were saved, and evil was defeated.

During Parasyte: The Grey‘s ending, Su-in is seen to have returned to her solitary life, working as a cashier at the grocery store, when Kang-woo comes to visit her. The young man has now become a member of Choi’s special task force, Team Grey, and the same offer stands for Su-in as well. Kang-woo leaves the protagonist with a letter written by her alter-ego, Heidi, in which the latter mentions how Su-in will never be alone in life again. Although Heidi has seemingly left Su-in to take full control over her body, the parasite is never seen leaving, which suggests that Heidi is still dormant-ly living inside Su-in’s body. Su-in and Heidi’s combined powers as mutants might once again come in handy in the future, for Parasyte: The Grey ends with a tease of the continuation of its plot, for not all of the alien parasites on Earth have been killed. The first season of the show ends with a young man coming to meet Jun-kyung at her Team Grey office, and he introduces himself as a journalist with special expertise on the alien parasites. The man, named Shinichi, apparently has some very important information about the parasites, and it is likely that a second, even bigger invasion is headed Earth’s way.

Notify of

Inline Feedbacks
View all comments
Sourya Sur Roy
Sourya Sur Roy
Sourya keeps an avid interest in all sorts of films, history, sports, videogames and everything related to New Media. Holding a Master of Arts degree in Film Studies, he is currently working as a teacher of Film Studies at a private school and also remotely as a Research Assistant and Translator on a postdoctoral project at UdK Berlin.

Must Read

DMT Guide

More Like This