Game Theory

Game Theory is a Magical Girl Lyrical Nanoha fanfic by Aleph (a.k.a. Immatrael) with input from EarthScorpion. The story can be found here on Spacebattles or here on Fanfiction.net. The story began on October 22nd, 2011 and finished on January 1st, 2013.

Game Theory's premise is that Precia Testarossa acts nicer to Fate, as she realizes it's a bad idea to abuse her sole mobile asset. While the fanfic is primarily about how this change affects the canonical story of Nanoha 's first season, Aleph and EarthScorpion also expand upon and reinterpret the series's setting and history. This new setting, referred to as the Gamesverse, has been described in a number of “infodump” posts on the story's Spacebattles threads. Aleph has also indicated there is a universe bible for the Gamesverse, but it will not be shown in it's entirety for some time as it contains implicit spoilers for Game Theory's ongoing and unwritten sequels. This wiki was created to store the information provided by the setting's creators in a way that is easily accessible for readers.

Summary
On the Garden of Time, four years before the Jewel Seed Incident, Precia Testarossa tells the recently “born” Fate about her origins. Fate is distraught by this information, but then Precia tells Fate that she could still be useful if she helps bring Alicia back to life. Fate immediately resolves to help.

Four years later on Earth, Nanoha Takamachi brings Yuuno Scrya with her to visit her friends Arisa Bannings and Suzuka Tsukimura. (As seen in Episode 4 of the original Magical Girl Lyrical Nanoha.) As in canon, a kitten in Suzuka's house discovers a Jewel Seed and grows to monstrous proportions. The kitten is named Vesta in this story. Nanoha and Yuuno prepare to confront the now-giant kitten before Fate intervenes. Fate defeats Nanoha handily, but then apologizes afterward and asks Yuuno to keep her away from the Incident.

However, Nanoha is undeterred. When a Jewel Seed appears at a hot springs resort, Nanoha arrives in time to see Fate and her familiar Arf seal it. Under Precia's advice, Fate reveals some of her motivations to Nanoha. Nanoha is almost willing to concede to Fate until Yuuno discourages her from doing so. Again, Nanoha is defeated. The next time the girls clash, a Jewel Seed activates in a hospital and reanimates corpses. A cancer patient named Chikaze Yoshida rescues a certain girl in a wheelchair from one of the corpses. The girls are themselves rescued by Nanoha and Fate, who work together to seal the Jewel Seed. However, Nanoha and Fate attempt to claim the Seed at the same time, resulting in a dimensional quake.

Fate is able to seal the quake and helps Nanoha recover afterward. The quake also affects the dimensional ship Asura, bringing the TSAB to Earth. Fate and Nanoha cooperate on the next Jewel Seed, and seem to be on the verge of coming to an understanding. The moment is broken by the appearance of Chrono Harlown, prompting Fate to flee, and Nanoha to escape with her. While Yuuno tries to convince Nanoha Chrono is basically a policeman, Nanoha finds him suspicious and refuses to listen. She does concede to meeting the TSAB later to hear them out, but then Fate appears at Nanoha's house, ready to tell Nanoha everything if she comes with her. However, Chrono also appears at Nanoha's house and attacks while Nanoha's mother Momoko watches. Nanoha is shocked to find that Yuuno is helping Chrono out. Making a decision, she flees with Fate.

After arriving at her penthouse, Fate takes Nanoha to the Garden of Time to meet Precia. Precia convinces Nanoha not to trust Yuuno or the TSAB before telling Nanoha about her motivations. Nanoha quickly resolves to help save Alicia even though it meets that she won't be able to see her family and friends for some time. Back on the Asura, Chrono is shocked to find that Nanoha was a native and that he had attacked Nanoha in her home – he was responding to a message from Yuuno that reported a sighting from Fate. Recognizing the danger of the situation, the Admiral Lindy Harlown equips Yuuno with a Device and brings in the backup team of Tiida Lanster, Heidi Zwischenfall, Rizu Jhanashdi, and Mei Ereignis. Back on Earth, Nanoha's family piece together what happened to her.

Seeing that Nanoha is feeling miserable from being separated from her family, Fate asks Precia if she can collect the kitten that was altered by a Jewel Seed, both for Precia's research and to give to Nanoha afterward as a present. Precia agrees to it. On Earth, Fate picks up Vesta and teleports her to Precia in the Garden of Time while Nanoha visits her mother and explains what happened to her. Nanoha leaves when another Jewel Seed activates in the city. Nanoha, Fate, and Arf confront Yuuno, Chrono, and the backup team over the Jewel Seed, which flees from both groups. While chasing down the Seed Nanoha runs into Arisa and Suzuka, who witness her flying. Nanoha is unable to prevent the TSAB from sealing the Seed, but she's able to meet with Arisa and Suzuka to explain what happened. Nanoha returns to Fate's penthouse and is surprised to see Vesta there, having been unaware of Fate's actions.

For the next two weeks, Nanoha spends her time hiding out at the penthouse with Fate while they search for Jewel Seeds. Through Nanoha writing a letter to her mother we learn that Precia suggested Nanoha should create a familiar for herself. Meanwhile, the backup team plants tracking devices around the homes of Nanoha and her friends, as well as their school. As for the Takamachi, Nanoha's father Shiro decides to teach Momoko self-defense in his family's style, in case she gets put in danger. This causes Momoko to display her own magical potential, as the Fuwa style uses low-level magic. The next day, the elite team of Zest Grangaitz, Quint Nakajima and Megane Alpine (who is pregnant with Lutecia) arrive on the Asura. Shortly after they arrive, Nanoha casts the Familiar Uplift spell on Vesta, turning the kitten into her familiar.

Some time later another Jewel Seed activates. Now including Vesta, Nanoha group tries to seal the Seed but it stymies their attempts until Zest arrives and defeats the Seed in one hit. Nanoha and Fate then fight an extremely one-sided battle against Quint and Zest, only escaping when Nanoha uses Starlight Breaker as a distraction. Another Jewel Seed activates the next day, but is sealed by the TSAB. Afterward, Nanoha visits her father before returning to the penthouse with Vesta. On the way back, the two are spotted by Suzuka and Arisa, who discover the location of Fate's penthouse. Both Suzuka and Arisa are themselves being followed by Megane's dragonfly summons, tipping the TSAB off to Nanoha and Fate's location.

That night, the TSAB group launches an attack on the penthouse. Fate, Nanoha, and their familiars manage to escape, but have nowhere else to go to. Nanoha then decides on a desperate plan to seal the final five Jewel Seeds, which have fallen into the ocean. Her group is successful in sealing one of the Jewel Seeds, but then the other four activate at once and take over a sunken submarine. The TSAB group quickly arrives and temporarily allies with Nanoha and Fate's group to fight off the Jewel Seed abomination. With the help of the others, Quint and Zest seal two of the four Jewel Seeds prompting the submarine to try and escape. Megane then unleashes her apex summon Hakutenou, which causes her to go into early labor. The two titans clash mightily, but the submarine overpowers and defeats the summons. Just as it seems the Jewel Seed monster will get away, Precia Testarossa casts a spell from the Garden of Time, destroying the submarine and teleporting Nanoha and Fate's group to the Garden itself.

As the TSAB is able to determine the location of the Garden of Time from Precia's spell, both Precia's group and the TSAB prepare for a final confrontation. On the TSAB side, Megane has successfully given birth to Lutecia and will be sidelined for the upcoming battle. Quint finds out that backup team member Mei is from a Belkan Berserker Lineage, and she discusses with Megane the possibility that Nanoha is from one too. The Asura is then contacted by Admiral Gil Graham. Graham and his familiar Aria Lieze help to coordinate the upcoming assault on the Garden of Time, and Graham sends his other familiar Lotte Lieze to help in the battle itself. On Earth, Arisa and Suzuka meet with Nanoha's family and they discover that they can also do magic. In the Garden, Fate confronts Precia about her health. Precia admits that she's dying and tells Fate to be strong for Alicia. Later, she tells Nanoha and Fate their roles in defending the Garden of Time. Using some of the Jewel Seeds to power the Garden's defensive systems, they will delay the TSAB for as long as possible while Precia completes a ritual to open a way to Alhazred. Precia also explains that she will be fitting Alicia with a Jewel Seed powered life-support system so she could survive the trip to Alhazred. After a suggestion from Nanoha, she names it the Promethean Metabolic Auxiliary Mechanism.

Finally, the TSAB attacks the Garden of Time. Nanoha mans the Garden's external defenses while Fate directs the Garden's robot army. While the Garden of Time is still boarded, the defenses appear to be effective at delaying the TSAB without any fatalities until Nanoha makes a crucial mistake. Taking advice from Vesta, Nanoha activates one of more powerful weapons on the Garden of Time which turns out to be a summon that acts as an automated targeting system. Horrified, Nanoha attempts to shutdown the Garden's defense system. She fails and is ultimately forced to destroy the defense system's core, causing a chain reaction in the Garden of Time. However, the summon is able to fire a shot that severely damages a TSAB ship.

When Nanoha destroys the defense system's core, the robots immediately fall offline allowing Zest, Quint, and Lotte to move towards Precia's location. The backup team soon finds out that the core's destruction activated one of the Jewel Seeds in the Garden of Time's reactor, which causes the robots to go berserk and assume strange new forms. The backup team is later rescued from a robot monster by Nanoha and Vesta, who helps them escape the Garden of Time. Fate and Arf confront Chrono and Yuuno but then temporarily ally with them to hold off the attacking robots and reach Precia. Meanwhile, Lotte confronts Precia's familiar Linith while Zest and Quint fight Precia herself. Ultimately, all the remaining parties on the Garden of Time converge on Precia's location. Once this occurs, Precia claims the ritual has been completed and asks Nanoha to go with her. Yuuno begs Nanoha to stay, but a simple plea from Fate sways Nanoha's choice. Apologizing to Yuuno, she goes with Precia's group. The TSAB group escapes the Garden of Time and watches as Precia's spell seemingly fails, destroying the Garden and causing a dimensional quake.

Sometime later, Lindy discusses the previous events with Admiral Graham. It turns out that there were no fatalities among the TSAB forces in the battle against the Garden of Time. Quint and Yuuno then return to Earth to deliver the news of Nanoha's death to her parents. Yuuno then gives them the Device he received from the TSAB. It is then revealed that Nanoha, Fate, Precia and their familiars are still alive, and that Nanoha had sent a message to her family telling them about her survival and also giving them a primer on magic. Precia explains that she had actually teleported the group onto a smuggling ship and then detonated the Garden of Time's reactor. In fact, she had abandoned her plan to go to Alhazred and did not tell Nanoha or Fate about this fact as part of a larger plan to trick the TSAB into thinking they were all dead. Precia then reveals that by studying the Jewel Seeds properties, she was able to find a way to revive Alicia without going to Alhazred. The Promethean implant wasn't a life-support mechanism, but rather a way to bring Alicia back from the dead. Precia shows the girls the sleeping form of Alicia, who then wakes up. Sometime later on another word, Nanoha, Fate, Arf, Vesta, Linith, Precia and the revived Alicia enjoy a picnic on a bright and sunny day.

Elsewhere, Gil Graham and his familiars discuss the condition of Hayate Yagami. It is revealed that the dimensional quake caused by the Garden of Time's destruction summoned the Wolkenritter, Graham prepares to put his plan into action.

The story is continued in Power Games

Trivia

 * The story is named after Game Theory, the mathematical study of strategic decision making.
 * Aleph has stated Game Theory was originally a fanfic where Precia traveled back in time after the events of canon Nanoha.