Magia Record Story I, the Reincarnated Overlord, Magnificently Thwart "THEIR" Conspiracy!!
The following is a summary posted on 4chan's /pmmm/ general.
Simply put, Rui Mizuki ropes in Seira Mihono to Kamiket in Kamihama, a convention made up of fans sharing, selling and buying fan made media hosted at a convention center down at the South Nagi ward. They became close friends after knowing that they are both magical girls, and also because Seira is the only one who knows about and accepts Rui's embarrasing secret (she has a heavy case of "Middle School syndrome a.k.a Chuuni-byo". The American equivalent would be an edgelord). Seira found out Rui was going to Kamiket this weekend and decided she wanted to join Rui seeing how Rui was really familiar with the place and Seira herself was interested in what kind of indies movies were available at the convention; under Rui's condition that only the 2 of them would go with no one else joining in to make sure nobody else finds out about Rui's secret. Even at the convention she cannot hold her excitement and starts going into character believing the convention is her "sanctuary" and the convention catalog guidebook is deemed "Hecatoncheires' Revelation".
They wait to enter the convention center a bit and besides exploring Kamiket, Rui's main objective is to go purchase the newest addition to her favorite indies game series and to meet her favorite indies author "MacQueen"; Rui had found the series when she was in middle school which she loves so much she has the entire collection installed in her laptop and refers to its creator MacQueen as "God". Seira checks to see what kind of works MacQueen makes, she looks him up online to see people have mixed reviews on his work and also he isn't very well known, a small time artist. On the way to meet the author at his booth, Rui accidentally bumps into a stranger who seems to be irritated that someone isn't at the convention yet. At the booth, Rui meets the two regular booth attendant girls and they're glad to see Rui but tell her that they've just found out someone used counterfeit money to purchase from them. It also seems other booths have been troubled by the counterfeit money and the convention staff is on the lookout for the criminal; but that isn't the only problem at hand, the very person Rui came to meet is apparently missing and the booth girls aren't able to contact him at all!
Rui's imagination comes to play here and she thinks this is all a big scheme plotted by "them/they" (an evil group working behind the scene to wreak havoc). She thinks the counterfeit scam and the missing MacQueen is all linked together and worse things are going to happen soon at the convention center. (Interestingly, Rui actually stopped a terrorist attack at her school by taking down the armed suspect). But as she starts imagining these possible situations, the convention staff is able to capture the criminal and they get a call from MacQueen who says he accidentally overslept bad and is rushing to the convention center right away. Rui is relieved to find that everything was just her imagination, so she calms down as she takes a picture with the booth girls; as they take a picture, chills run down Rui's spine because it feels like somebody is glaring at her from somewhere in the convention at that moment.
Rui tries to calm down thinking it's all her imagination and explores the convention more with Seira. As Seira looks through the thick and heavy convention catalog looking for her favorite movie director's booth to visit, Rui realizes something from what the convention staff mentioned earlier. The convention booths are ordered in alphabet-number system and including the booth she came to visit, the booths that the counterfeit money was used were C6, H14, N2 and O2; she quickly realizes this is the chemical formula for Ricin , a lethal poison that can kill humans easily. She starts imagining that the whole counterfeit scam was indeed plotted by the messenger division from "them", to send out the method of wreaking havoc to the other members in secrecy. As Rui was confused as to how the scheme is going to happen, Seira says she's hungry and wants to eat lunch. This reminds Rui there are food vendors right outside of the convention center and thinks "they" will be spiking the food served there with the toxin and quickly tells Seira they need to rush outside right now to stop from all of this from happening.
Rui and Seira rush out to stop the food vendors from serving their food only to find people outside already digging into their lunch. Rui is stricken that she is too late and many people are going to die at her favorite event. But to their surprise, everyone seems fine after eating their lunch and Rui checks to see what's up by activating her magical girl ability which is "the ability see how close someone is at death's door". It works closer to fortune telling and apparently by intervention the living's fate can be changed even if they are really close to "death's door". As she checks everyone she realizes nobody is even close to dying and realizes her imagination finally took the best of her and she caused too much trouble for her own good. A bit ashamed, she apologizes to Seira for the trouble and decides to get lunch. As they prepare to dig into their food, Rui, eager to play the next part of her newly acquired game, tells Seira she will install the game while they eat lunch, to find, to her shock, that on her laptop screen there is only a black screen; a black screen reflecting her face which shows with her magic that she is close to death.
Rui in shock tells Seira what happened and, remembering the chills she felt earlier when she took a picture at the booth, checks the photo they took. Just as she thought, in the photo she sees a man glaring at her which she comments she feels like she remembers seeing the man somewhere. Wondering if it's only her or if it's also the booth girls who are in trouble, she quickly rushes over to the booth to figure out who is being targeted. At the booth, using her magic Rui sees that neither booth girls are in trouble and they seem to know the man who was glaring in the photo. The man goes by the name "Miranda" and was apparently a big time content creator who was so popular he usually has long lines waiting to buy his creations at these conventions. Just as they discuss the matter, MacQueen finally arrives to the scene and to Rui's dismay he is seen to be the closest to death's door.
Rui also realizes there's someone else besides MacQueen and it is Miranda himself. Sensing danger, Rui calls out to Miranda, demanding to know who he is and what he wants. Miranda is a little surprised he is being asked to stop, and politely tells her he just came by to see MacQueen since he is also a big fan of MacQueen's works. Rui remembers his face now and it was the irritated man she bumped into earlier and asks why he really wanted to see MacQueen and bluntly asks him whether he wants to kill MacQueen. Miranda is surprised at Rui's provocation and is confused why she's asking these things. Finally Rui tells him to stop acting dumb and that she saw him with a knife in his hand earlier which he hid in his pocket. Realizing Rui saw his weapon (which was a bluff by Rui), Miranda finally confesses that he is here to seek revenge on MacQueen. Thinking she can finally apprehend Miranda from committing a crime, Rui tries to stop him but Miranda brings up that the only issue is that he doesn't have a knife as he pulls out a gun from his pocket.
As Rui and the others are surprised as to how he was able to sneak a gun into the high security convention, Miranda tells them that being a big time content creator allowed him to bring in a 3D printer for his merchandise and he secretly printed a gun out to kill MacQueen. When asked why he wants to kill MacQueen, Miranda says that in the latest addition to MacQueen's series, an alternate ending hinted that his favorite sub-heroine in the story may have had a former lover before. Miranda was in shock that his favorite sub-heroine loved someone else before and could not contain his dismay. It bothered him so much he became angry at the series and in turn started to hate the series which once he loved. Dismayed by the result, he couldn't think of any way to ease his anger besides getting revenge at its creator who was MacQueen; and of no better way to punish MacQueen besides killing him.
As people are screaming and calling for security with a gun on the premise, Rui realizes that Miranda was mistaken and quickly takes out her laptop. As Miranda is about to shoot MacQueen, Rui stops him by telling him to stop and look at the screen. To Miranda's surprise, there is a cut scene he has never seen before. Rui explains that this is actually the second part to the alternate ending, only available after clearing the entire game with the alternate ending and it shows that the sub-heroine faked her story about her former lover in order to protect the user character from danger in the story. Being too angry to continue playing the game and realizing he had made a foolish mistake, Miranda finally loses his anger and gives up trying to kill MacQueen. As he is captured by convention security, MacQueen thanks Rui as Rui checks both of them to see that both are clean from dying and she was successful in changing both of their fates thanks to her actions.
After the incident, Seira asks if Rui wasn't scared that she would get shot by Miranda and Rui tells Seira that she always prepares chainmail under her clothes so she should be fine if she were to be stabbed or shot; Seira tells Rui that she'll just act as if she didn't hear that from Rui just now. Rui also mentions that she also had an added layer of protection by having a heavy blunt object on her in case things did get more out of hand and it should be able to stop a 3D printed bullet from reaching her. Seira wonders what kind of blunt object could be sneaked into the convention center which had high security,and realizes that what Rui had on her was the magically enhanced Hecatoncheires's Revelation. A job well done, Rui is glad she was able to save the day which was a piece of cake for someone who is a reincarnation of the supreme overlord.
- *The chemical formula C6H14N2O2 actually is for a type of amino acid that is essential for humans known as lysine. Ricin is a toxin which does not have the same chemical formula. It is unknown if this is mistake on f4 writer's part due to Lysine and Ricin both having the exact same spelling in Japanese(リシン) or if they are poking humor at the fact that people with chuuni-byo have very shallow academic knowledge since most of it comes from their favorite video game, novels, comics, etc.