Epitaxy of the Projected Curved Surface

Shaei Kyokumen no Epitaxy (射影曲面のエピキタシー) is a Drama CD released on November 9, 2012 as part of the limited edition release of Heijikyokusen no Epigraph.

Plot
One sweltering day in August, Hiyajou Maho arrives in Akihabara. While assuring well-meaning passers-by that she is not a lost child, she makes her way to the lab, thinking, "Just you wait, Future Gadget Laboratory!"

Mayuri and Okabe are walking to the lab, and Mayuri is in high spirits despite the heat. When she explains to Okabe that it is because the lab has grown so much, he laughs that he is not happy about it for… it is but a matter of course for this mad scientist's charisma!

They encounter Luka, Faris and Moeka on the road. Luka is in a high fluster because Faris is on a special mission to try to convince him to work at May Queen during their Miko-Miko week. Fantastical reasons are given. Golden sunrises, messengers of the divine, and the Holy Grail are named. However, it turns out that Faris asked Moeka, but Moeka's condition was that Luka work with her as well, so it would be less embarrassing.

Luka is stuck between a rock and a hard place as on top of Faris's assurances, Mayuri is ecstatic about working together at May Queen, and Moeka joins in with "Cuteness is Justice." Luka begs "Kyouma-san" for help, but Okabe seemingly rejects the plea as unfitting for a mad scientist. Okabe does, however, suggest that they get out of the heat and move to the lab. Mayuri notes that Moeka seems to be suffering. Moeka agrees that she is "melting", so the group moves forward on to the lab.

They come upon Daru and Suzuha outside the Braun Tube Shop as Daru finishes putting a new derailleur gear on Suzuha's bike. Daru notes that he thought there wasn't a Round Table Meeting today. With maniacal laughter, Okabe tells the group that the natural order has opened the way for them to hold a meeting; much to Faris's shock, who thought they were going to continue convincing Luka. Okabe overrides her for the moment, though. When Suzuha wonders about Kurisu not being present, he assures her that Kurisu must be in the lab already, being an "Experiment-Loving Girl", after all.

Upon entering the lab, however, they encounter not Kurisu but a "little girl". Hiyajou Maho seeing them wonders if she got the wrong address. She apologizes that she got the wrong place, but then steps on Okabe's toes when she mentions that she should have realized it since that "high-sounding name" did not fit this place filled with junk. She tries to leave, but Okabe calls her to a halt, calling her "Small Animal!" This riles Maho, but Okabe continues on to call her a spy of the "Organization", hardly believing that they would send even a child in to infiltrate.

The others treat her like a child too, but when Faris offers to help her find where she needs to go, Maho puts aside her frustration to ask for directions. Okabe is shocked that they are getting friendly with an agent of the "Organization". He warns them that she might look like a child, but have the brains of an adult. Maho has no clue what he is talking about with "Organization" and asks Okabe if he is alright in the head. Okabe takes a hit at this but recovers, going on to praise her for finding this Future Gadget Laboratory. However, this Mad Scientist, Hououin Kyou- Maho interrupts and asks him to repeat that. Thinking the Organization's agent is out for more information on him, he restarts his "terrifying" self introduction. Maho turns instead to Mayuri who confirms that this is the Future Gadget Laboratory, when asked.

Hearing this Maho realizes that this must be the place where "she" is after all. Just then Kurisu enters and is surprised to see everyone gathered but shocked to see Maho. As Maho and Kurisu greet each other, the others are confused that Kurisu calls her "Senpai". Maho turns and belatedly introduces herself as Kurisu's senior at the university research institute in the US, Hiyajou Maho, a full-grown woman! The others collectively cry, "Whaaaaaa!?"

Moeka summarizes what they have heard as, Maho had grown impatient because Kurisu had not returned, and therefore come to Japan. Suzuha gets that but still looks doubtfully at Maho. Kurisu assures them that in both age and university year, Maho is her senior. Maho adds that she was not impatient and had not come just because she wanted to see Kurisu. They need her for the furthering of their research. Kurisu explains to the others that her university is currently working on a new sort of A.I. She questions Maho about the research, Amadeus. Given what Kurisu arranged before leaving, there shouldn't be that much of a hurry for her to return. Maho protests that even so, originally Kurisu was supposed to come back right after her lecture, and for Kurisu to stay here for this suspicious lab...

Okabe starts chuckling off-kilter at the word "suspicious", which he finds a compliment of the highest order. Further weirded out, Maho asks Kurisu just what this "Hououin" guy is. She totally cannot understand him. Kurisu asks her to simply not think too deeply when it comes to him. Even if Kurisu says that, Maho protests that he has been acting weird for awhile. He even called Kurisu "Assistant". Okabe assures Maho that Kurisu recognizing his brilliance begged to be his assistant. Kurisu cuts in to assure him that that is all in his head.

Maho turns to Kurisu in puzzled distress, not being able to understand Kurisu very well anymore. Why would Kurisu put aside her important research to be in a lab, er junk shop, like this? Kurisu hesitates to answer, and Okabe speaks his affront in a drawn out, condescending tone. Maho has quite a lot of nerve to be calling someone else's lab a "junk shop". Maho, however, has seen the "gadgets" and hardly thinks they can be called as such. Okabe takes a hit again, and demands Daru speak up and say something, which turns out to be a bad choice as Daru begins with "Frank Lolies are the best!!!" His further outburst is stopped by Kurisu, who hastens to assure Maho that she does not have to know what Daru just meant.

Maho tells Kurisu that she should hurry and return after all she might turn strange with frightening speed if she stays here. Faris protests that they aren't strange, nya! Maho apologizes quickly that she said too much, but Faris continues. The memories of their past lives are simply sealed, nya! Maho turns to Kurisu that they really should leave now, but Kurisu begs Maho to wait. Maho, noticing Kurisu's attitude and hesitation, tells her that if she has a reason she wants to be here Maho hopes Kurisu would tell it to her.

Mayuri asks Luka quietly if Kurisu will be going away… They both think it will be lonely if Kurisu returns to the US. Okabe assures them that Christina won't be leaving. Maho asks him pointedly how he can be so sure. Okabe digs in, asking her if she wants to know. In that case, he'll tell her. It is because, she, Christina, admires him, Hououin Kyouma--! "Christina" shuts him down with that is the one thing it is not. He continues to tease Kurisu even bringing up her avid @channel use. Maho asks what @channel is, and Kurisu falls accidentally into @channel lingo as she threatens Okabe that if he tells her senpai any more weird stuff she will make him pay. Okabe laughs at her slip-up as Kurisu has an orz moment.

Maho is shocked at this new side of Kurisu and the two's whirlwind exchange. Okabe turns to her and says, "That's how it is, Assistant-Loving Girl." Maho reacts dumbfounded at being dubbed such. Okabe teases that she was so lonely without "Assistant" that she came all the way here to see Kurisu. Maho tries to insist that it was only because of their research, but Hashida springs in with a girls-love outburst until Suzuha finds herself bringing pain down upon him, apologizing that her hand just slipped.

Okabe cuts in flaunting to the "Assistant-Loving Girl" that in any case Kurisu would not be returning for the meantime. Riling at the nickname again, Maho asks just what they all are!?

That night at Kurisu's hotel Maho is having trouble sleeping and she and Kurisu start talking. Maho apologizes for crashing even into Kurisu's hotel room to which Kurisu good-naturedly teases her.

Maho asks Kurisu if the D-mails she was told of earlier are really real. Kurisu admits that she herself is only half-convinced. However, the chances it is real are high. Maho admits that if Kurisu is willing to say that, it probably is. However, if mails that can change the past exist they could mess with the standard order and sense of the world. That something like that could be invented in a place like that is surprising. Kurisu admits that its creation was largely the result of coincidence.

Maho muses that even so they are somehow capable of it, otherwise Kurisu would not have a reason to stay there. Kurisu is at a loss for a reply, and Maho continues to ask about Hououin. Kurisu tells her that he is Okabe Rintarou. Hououin is just something he made up. Maho fails to understand the meaning of his doing so, and starts listing his bad points. He's excessive and rude. With a pause she asks Kurisu if it really is not true that Kurisu asked to be his assistant. Kurisu assures her that that is just Okabe saying whatever he wants. Relieved, Maho muses that that is of course. For Kurisu to do something like that is just… Kurisu cannot reply.

Maho continues that if the D-mails are real it should be taken out of their hands soon and turned over to a proper research facility. Kurisu replies that that might be true, but even though it was accidental, the machine is something "they" created, and… When Maho prompts her, Kurisu tells her that those guys really aren't bad people, so… Maho is surprised at Kurisu's affection for them. Kurisu hides her fluster by suggesting they sleep, since Maho must be tired from her long flight. They wish each other good night.

The next day, Maho visits the other lab members in Akihabara and asks them about what sort of person Okabe is. To Luka he is his benefactor who saved him and for another important reason. "Ah! But not in a weird way!" Moeka is unable to tell her because Maho forgot her cellphone back at Kurisu's hotel. Faris finds him interesting and he does not treat her differently than others. Further, they have a looong and deep connection spanning several past lives, nya! To Suzuha he is like an adult. She slips up explaining that he used to change her diapers and give her baths. Mayuri further confuses Maho when she tells her that Mayushii is Okarin's hostage and Daru-kun is his "favorite light saber"!

When Maho voices her confusion, Mayuri says that Okarin is Okarin, just like that, and Daru tells her that Okabe is simply a chuunibyou, good-for-nothing guy who always says strange stuff. It would be nice if Okarin could keep his pushing him around at a minimum. This leads Maho to question why they are together with him. Mayuri answers gently that it is surely because Okarin holds everyone as important. To him each of the lab members is precious. For their sake he would surely do anything. That is why everyone loves him.

Daru won't go as far as to admit it when asked by Mayuri but tells Maho that Okarin is someone to try his hardest for others rather than himself, so when it comes down to it, it is alright to rely on him. Mayuri is sure that if Maho gets to know Okarin better she will come to see his good points.

Maho changes the topic and asks if like earlier Kurisu is always like that around them, laughing and getting angry from the bottom of her heart… Maho pauses and retracts her question telling them never mind. It's fine. Mayuri and Daru are confused as she thanks them and leaves.

That night Maho sneaks into the empty lab to send a D-mail. As doubtful as it seems, since Kurisu said that it could, the Phone Microwave must work. Maho fumbles around trying to figure out how to use it. She hesitates. Mayuri had said those things, but still…

"What's the matter? Why are you hesitating?" Maho whips around at the sound of Okabe's voice coming pompously from the living area. Maho calls him "Okabe Rintarou" and he shouts back that he is Hououin Kyouma!! Maho tosses that point aside and asks him what he is doing here this late. It couldn't be he had guessed she would come here. He chuckles that of course he can see through an agent of the Organization. However, she hits the truth right on target by guessing that he was actually stuck in the toilet with an upset stomach when she first came in, and proceeds to lecture him on making sure to clean up properly after himself.

Okabe turns the conversation back around on her. She tells him that even if he wants to stop her from sending a D-mail, it is no use. For Kurisu's sake she must send a mail telling her not to come to Japan. That girl's intelligence is something the world of neurological research cannot be without. She does not have the free time to hang around in a place like this. It's for the sake of the world and Kurisu's own personal good if she never came to Japan at all. That is why, Maho apologizes but Okabe cannot stop-. He cuts in telling her that he does not intend to stop her, which trips Maho up. Okabe tells her that if it really is for Christina's sake then it is fine if a D-mail is sent. However, he says that Kurisu should be the one to see the mail and decide about sending it. He tells Maho to not forget that and without a further word coolly leaves the lab.

After a long pause, Maho tries to send the D-mail for Kurisu's sake, but Okabe words have stuck and she finds herself unable to do so.

It is another hot day. Okabe, Daru and Mayuri are walking to the lab when they come upon Faris and Moeka once again trying to convince Luka to work at May Queen. Suzuha shows up as well, and asks if there will be another "Whatever-it's-called Meeting". Since the last Round Table Meeting ended up not happening, after all, Okabe decides it is a good idea to hold one and tells Mayuri to contact Kurisu. However, it turns out that is not necessary as Kurisu comes running up to everyone out-of-breath. Noticing Okabe, she calls out that they have good timing.

Setting aside Okabe's teasing about her growth as an assistant to come before being summoned, she asks him if he has seen Maho. However, no one has seen her. When Luka asks if something is wrong. Kurisu shows them a note that Maho left behind in Kurisu's hotel room that morning.

Moeka reads it aloud, "I'm sorry. I will give up on trying to make you come back. I'll be leaving first." She further writes that Kurisu should do the things she wants to do. Many of them think Maho's departure is very sudden, and Kurisu having noticed that Maho went somewhere last night is worried that something may have happened. She turns to Okabe and asks if he knows anything, but he feigns ignorance, saying it is not strange for someone who suddenly showed up to quickly leave as well. He waves aside Kurisu's protests and declares that today they will definitely hold their "130th" Round Table Meeting, and tries to usher everyone up the stairs to the lab. However, Kurisu knows he is hiding something. She tells him to fess up and demands to know what happened with Maho. They bicker all the way up the stairs until Maho suddenly opens the lab door and asks them to be quieter in the stairwell.

Kurisu and Okabe are stunned. When Kurisu asks her about her leaving, Maho tells them she was planning to but decided to stay awhile longer, after all. She vaguely tells them that it is because there are "various things" that seems interesting here.

Some of the labmems reactions range from confusion to suspicious about Maho's vague choice of words, but Maho adds on that she is planning to stay at the lab while here rather than bothering Kurisu at her hotel, though Kurisu argues otherwise. However, Okabe simply starts fuAHAHAHA-ing and declares Maho "Labmem number ☆ 009!", shocking everyone else. Except for Maho, that is, who declares that that sounds interesting. Kurisu is surprised at both of them. Mayuri is overjoyed that the lab is growing again. Daru has no problem whatsoever with Maho staying, fully intending to keep playing his eroge at that lab, which makes Suzuha feel apologetic (for her father's behavior).

Okabe announces that at this time the D-mails should work, so they should start experimenting. Maho is interested but pauses when she realizes that Okabe said "at this time". Moeka then explains that the D-mails can only be sent between noon and six in the evening. Okabe bursts in with a laugh and orders "Assistant" and "Loliko" to start the preparations. Maho takes issue with being called weird names and demands to know that Okabe had said all that last night knowing she could not send a D-mail anyway. Okabe just tells her to not sweat the small stuff and continues his laughter. With exasperation, Maho reflects that maybe she should just leave, and Kurisu tells her that might be better.

Cast & Crew

 * Maho Hiyajo
 * Kurisu Makise
 * Rintaro Okabe
 * Mayuri Shiina
 * Itaru Hashida
 * Kiryuu Moeka
 * Luka Urushibara
 * Akiha Rumiho
 * Suzuha Amane