'Day One' Ending Explained & Series Recap: What Does The Last Scene Suggest?

The new Spanish science fiction thriller series streaming on Prime Video is a hit-or-miss affair at its best moments, with most of its concepts and characters being too shallow to take seriously. The 6-episode series is centered around a computer prodigy named Ulises Albet, who suddenly receives a mysterious video message from his former best friend, Samuel Berrerra, ten long years after he had left Barcelona to live a secretive life. Overall, Day One might still be entertaining if you’re looking for a mindless thriller with elements of drama, but it fails to be anything worth remembering or rooting for.

Spoiler Alert

What is the show about?

Day One begins on a very special day for the tech industry, as one of the leading tech companies in Spain, DISKIN, is about to hold a press conference at their headquarters in Barcelona. The founder and CEO of the company, Damian Diskin, is himself about to address the hundreds of journalists gathered at the auditorium, and thousands more joining the event online. Although such a conference is a yearly affair for the company, there are credible reports that state that DISKIN is about to launch something revolutionary in the tech field. As Damian Diskin takes the stage and thanks everyone for their presence, he reveals that his company has indeed been working on something extraordinary, which had only been thought of as possible in science fiction. Finding it much more relevant to lead research into the human brain instead of farflung matters like outer space, Diskin is confident that his new product will change humanity forever.

But the world will have to wait 7 days before the launch of this revolutionary device, named Day One, as the press conference turns out to be just a teaser to create hype for the main product. All while Diskin addresses the world at the auditorium, an important client and also tech partner at his company, Samuel Berrerra, hurriedly walks towards the security room before sneaking into it, since he is definitely not supposed to be there. Samuel goes through the files at the main terminal, clearly looking for something particular, and he is eventually able to find the file and transfer it onto a thumb drive he had been carrying. What the file contains is truly shocking, as security camera footage shows a man, evidently a medical test subject, suddenly becoming very violent and aggressive, and repeatedly banging his head against the wall until he starts bleeding and collapses. 

Once the transfer is over, and he is able to sneak out into the open, Samuel asks the chief engineer of the company, Beth, to join him for a coffee, clearly to warn her about something. After the conference ends, Diskin is eager to sit with the two most important individuals at his company, Beth and Samuel, which mars the latter’s plan. As he finds out that Samuel has broken into the security room and taken files away, he immediately instructs his guards to arrest the man. However, it is already too late, as Samuel has fled the scene and also sent a mysterious but heartfelt video message to his estranged best friend, Ulises Albet, warning him that something sinister is going on at DISKIN.

What exactly is the Day One device?

We are first introduced to the marvels of the Day One device through Rebeca Bustos, the young woman who gets caught up in the whole mess and then gets offered the device by Diskin. On the surface, the Day One is a pair of contact lenses with virtual reality augmentation that basically turns the vision of whoever is wearing them into a smart screen, per se. One can look at anything and get in-depth information about it in real time, which makes it the most advanced tech product of the time. Rebeca solves the complex programming problems during the hackathon with the help of the Day One she is wearing, as it can solve any equation or mathematical problem within seconds. She is able to get information about anything, and the idea is that police officers and security personnel will also be able to identify people with the help of the product. 

Later on, when Ulises himself wears the Day One device and asks it to identify the emergency exits at a building facility, the device is able to do so very easily. Not only does it use information from the camera embedded in it, but it is also able to browse the internet and fetch all results about a place or thing within mere seconds. It also has an AI assistant, called the Mother, which creates a concise report of all the information and presents it to the user in a simple and helpful manner. In a brief sense, the Day One device is all the smart displays and supercomputers and AI assistants put into one, and instead of being restricted to a big or bulky form factor, it has been embedded into normal contact lenses so that users can access it in a hassle-free manner.

However, there is a concerning secret beneath the surface, as the Day One device actually has a completely different purpose than stated. In reality, it is a device that is to be used for unethical surveillance, and it can even tamper with any tech that the user is looking at. This becomes evident when Rebeca simply looks at the videos from her phone, intending to upload them, but Diskin and his engineers remotely control her phone, through her simply looking at it, and delete the videos. Much more concerningly, the Day One device is embedded with something called the Synchrotron chip, which is an extremely small but powerful processor that has the ability to trigger effects on the user’s brain through their optic nerve. The processor specifically affects the part of the brain that controls emotions, meaning that the Day One device can be used to control its user’s emotional state and associated physical attributes. The engineers at DISKIN, under the orders of their boss, are the ones who control and manipulate the users’ emotions, which is highly illegal and unethical. To control the emotions of humans remotely is the only true purpose of the Day One device, and this is why the test subject in the video found by Samuel at the beginning of the show had suddenly turned violent. Later on, Diskin manipulates Rebeca’s device as well, making her feel disoriented and scared of Ulises. 

How was the device created?

There is a strong story behind the creation of Day One as well, for it is actually Ulises’ invention that is being used by Diskin for his own personal agenda. Ten years back, when Ulises was a brilliant computer whiz and had started his own company with his best friend, Samuel Berrerra, and his girlfriend, Paula Castell, he had invented the Synchrotron chip to help humans emote and understand others’ emotions better. The main reason for his invention was to help his younger sister, Anna, understand human expressions, as she was unable to do so from her very childhood. As Anna did not understand expressions and emotions, she was mostly expressionless, because of which she was incessantly bullied at school and even in her neighborhood. The bullying had such a horrific impact on her that Anna took her own life when she was just a teenager, unable to bear the cruelty. 

Thus, Ulises’ plan failed, despite him having made a groundbreaking invention, and as he was absolutely shattered by his sister’s death, he left Barcelona immediately, severing all ties with Samuel and Paula, and settled for a new, lonesome life in a village. With Ulises out of the picture and Paula having left the company soon afterwards, the Synchrotron chip technology was now Samuel’s, and after a few years, he went on to sell it to Diskin Tech. Just like the protagonist, Damian Diskin was also driven by a very personal loss, as he had lost his beloved mother at a young age. Even as a little boy, Damian had grown used to the sight of his abusive father assaulting his mother on a regular basis, and it was this horrific torture that had led to the woman’s death. Therefore, when he grew up to become a tech innovator, Diskin decided to invent some device with which he could easily manipulate anyone’s emotions and bring an end to conflict of all kinds. With such a magical device, he could have turned his father into a benevolent and loving man within seconds, which could have prevented his mother’s death. When he found out about Ulises’ invention and was able to buy it, Diskin went ahead to make the Day One. While his intentions might have been genuine, Diskin basically tries to play God with his device and soon turns into a villain, as he is willing to sacrifice multiple lives just to ensure that Day One gets to be released.

Is Ramisa able to execute her plan?

While the professional assassin, Ramisa Biran, boasts about not leaving any loose ends, she fails to notice how she herself is being considered a loose end by her employer. Ramisa had been appointed by Damian Diskin to kill anyone who would create obstacles for his company, with the first two targets being Samuel and Paula. But with time, Ramisa starts to demand more money for her services, as she starts making a personal plan of her own because of the presence of a man in her life. Despite being a hardened criminal who had even committed murders in other European countries earlier, Ramisa now finds herself sincerely in love with her boyfriend, Lucas.

Although Lucas is an investigative journalist by profession, and he is even researching the very murders committed by his girlfriend, Ramisa wants to settle down with him, and possibly even admit her crimes to him in the future. She makes a solid plan of quitting her profession very soon to move to a different country and live a peaceful life with Lucas, for which she needs even more money, and so she keeps extorting Diskin. However, her plan completely fails when Lucas finds out about her identity and refuses to be with her anymore. All of a sudden, her beloved boyfriend becomes a loose end whom she cannot let live, and so Ramisa kills Lucas and concentrates on working for Diskin. In the end, she is killed by Alba, and despite her best efforts, Ramisa’s life ends in an insignificant manner.

Can Alba’s betrayal be caught?

One of the police officers, Alba, had been working on behalf of Diskin, letting the CEO completely control and manipulate the investigation and receiving remuneration in exchange. By the end, he tries to create a false narrative about the whole incident, also concealing his involvement in Ramisa’s death. He states that Samuel was Ramisa’s client, but she had eventually killed him because of some argument. Alba comes up with a similar story to explain Paula’s death, and given how he has been manipulating the crime scene from the very beginning, it will not be too difficult for him to prove the theory either. But in the end, one of the younger police officers, Corbella, finds a crucial piece of evidence against her senior. Alba had earlier visited Ramisa’s apartment to kill her, but had fled the scene upon finding only Lucas there. The security cameras there had clearly recorded the police officer, and Corbella now finds this video. She pretends to be on Alba’s side and makes him confess his crimes on record, having already planned with the other senior officers to use this recording to have Alba finally arrested.

Was Diskin exposed?

The most effective way for Ulises to expose Diskin’s unethical measures is to get photographic evidence of the Synchrotron chip that has been embedded inside the Day One devices. Because of the extremely tiny size of the chip, photos of it can only be taken using a high-powered and precise microscope that is kept at a research facility in Barcelona. Ulises takes the device that had been given to Rebeca to this facility and manages to get photos of the embedded chip as well. But before he and Rebeca can escape the place, they are taken hostage by Alba, who then takes them to the DISKIN compound. The plan to expose the company through the photographs is now out of the question, but the protagonist does finally manage to lay bare the truth to the world. He does so in the most dramatic fashion, with the help of Beth, who had realized the true intentions of her boss and turned against him. As Diskin counts down the timer to launch his latest innovation on the stage, Beth plays the video of the test subject acting erratically on the screen in the auditorium. Ulises then announces his real identity, and also talks about how Diskin had been trying to take control of his customers’ emotional states using the chip embedded in his device. Thus, in just a few minutes’ time, Damian Diskin’s world comes crashing down, and his evil megalomaniac nature is exposed. Feeling guilty about having participated in such a cruel plan, Beth willingly agrees to cooperate with the police and face the consequences of her actions. 

Does Salvador receive treatment for his ailment?

Throughout the series, the main police officer earnestly investigating the case, Salvador, suffers from moments where his body suddenly freezes and his vision and perception get blurry, allowing the ones he is chasing to get away. This is all part of his struggles with a brain tumor, which is at such a critical stage that the doctors have openly told Salvador he does not have very long to live. But he does not share this with anyone other than his husband, Rafa, who is naturally very distraught about the situation. Therefore, when DISKIN offers to pay for an experimental treatment that they have come up with, which can heal Salvador’s brain tumor very easily, Rafa is ecstatic. He agrees to the plan even though Salvador had already turned down the offer, since it was basically Diskin’s attempt to control the investigation through the police officers. In the end, we do not get any confirmation whether Salvador is going to receive treatment or whether any such experimental treatment even exists. Diskin could have simply lied about it to get the police officer under his control, but he had failed against Salvador’s strong principles. In the end, Salvador retires from the police force and goes away to spend time with Rafa, either having embraced the fact that his life is going to end soon or with the hope that some sort of treatment might still be able to help him.

What does the last scene suggest?

In Day One’s ending, Ulises finds a box left to him by his dear friend, Samuel, who had become an expert on creating holographic AI replicas of humans. Ulises had already interacted with an AI version of Samuel earlier, and he now realizes that the box contains a holographic AI version of his beloved sister, Anna. Through a heartfelt conversation that is possible only because of the technology, Ulises accepts that Anna’s death was not his fault and that he could not have helped his sister any more than he had. Had he been more controlling of Anna’s emotions, then he would have turned exactly as villainous as Damian Diskin. Thus, he finally accepts Anna’s fate and moves on from the loss, possibly continuing to be in touch with Rebeca, who had already become a sister figure to him. The way in which the holographic version of Anna speaks, which had been designed by Samuel, of course, also seems to suggest that Samuel had had romantic feelings for Anna, which he could never confess to her in person.

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