Note that the events here assume the Outsider is alone during his journey, and only deal with either major events (events that change the ending) or story events. This also assumes the Outsider skips the optional events such as the Field Cave. Events listed are in order of recommended level if there is freedom to choose another first.
The Outsider Who Loved Gensokyo takes place in the world of Gensokyo, where a person from the outside world is lured into and later is known to be a chosen Emissary for Gensokyo, a tradition that brings someone in from the outside world every 200 years.
The game begins by the player naming the Outsider. During a visit to Japan, the Outsider visits a shrine, where he spots a mysterious women and follows her. He is outrun by her and he finds himself lost in a bamboo forest, where he is attacked by a youkai named Mystia Lorelei. Fujiwara no Mokou saves the Outsider in the nick of time and escorts him back to the Human Village, where he sees other youkai, and meets Hieda no Akyuu, and Keine Kamishirasawa. They explain where he had ended up and advise him to go home. The Outsider refuses to go home, to Keine's and Mokou's dismay, reasoning that he wishes to explore the world of Gensokyo. Mokou decides to hand him off to Reimu and make their way towards the Hakurei Shrine.
At the shrine, the Outsider meets Reimu Hakurei and Marisa Kirisame. The both ask him how he got there, and are told he followed a women in a purple dress. The incident solvers are taken aback, and immediately guess it was Yukari Yakumo who lured him there. The Outsider wishes to meet Yukari the next day, and decides to stay at the Hakurei Shrine for the night before they head out.
Reimu and the Outsider reach Yukari's House and encounter Ran Yakumo. Reimu and Ran fight in the sky much to the Outsider's amazement. During this altercation, Yukari sneaks up behind the Outsider and greets him, along with Aya Shameimaru. Yukari explains to the Outsider he is the Emissary: A person chosen every 200 years to bring gifts to the youkai of Gensokyo and spread the legends of them to the Outside world. Aya is there to get information and spread the news. Without much else Reimu can do, she decides to head back to the shrine after the Outsider is handed a weapon and the Gem of Boundary: A tool designed to protect the Outsider from the special powers of the inhabitants of Gensokyo.
Reimu and the Outsider run into Yuuka Kazami along the way, who makes known she has contempt towards his status of Emissary, and berates him on the spot. Yuuka says she wants to fight the Outsider at some point, to the duo's chagrin, and heads to the Garden of the Sun. The duo reaches the Hakurei Shrine, separate, and the Outsider begins his journey.
To the Human Village
The Outsider decides to make his way towards the Human Village as his first destination to receive guidance on where else to go. Along the way, he is splashed by Murasa Minamitsu, who says she may have drowned him if he fell into the water. The Outsider deducts the Gem of Boundaries stopped that from happening. Murasa leaves him alone to head to the Human Village, where he meets Akyuu. Surprised by the turn of events, the Outsider is directed towards Keine, who tells him to go to Kourindou: A place where he may find goods for his journey.
The Garden of the Sun
Before heading to the Human Village, the Outsider decides to head to the Garden of the Sun to ask Yuuka what the problem was. He meets her there only to be blocked entry to Nameless Hill until he fights her. When asked a question, he doesn't get much out of her and is told to grab a mushroom from the Forest of Magic and bring it to her.
Kourindou is only to the West of the Human Village. After defeating monsters and gathering equipment, the Outsider finds Kourindou, only to be blocked by Mystia Lorelei, seeking revenge after being hit by Mokou, and begin a battle. After the fight, the Outsider insults Mystia's singing, offending her greatly, and he receives a cup as part of a deal they had before the fight.
The Outsider heads into Kourindou, where he meets Rinnosuke Morichika, the owner of the shop. Rinnosuke gives the Outsider a scroll that allows him to identify objects he finds in his journey, and finds out the item he received from Mystia was a damaged Holy Grail, granting him power because of his status of Emissary.
The Outsider heads back to Keine for guidance and is told to stay away from the Bamboo Forest of the Lost, visit Rinnosuke every once in a while, and head to the Forest of Magic to see if Marisa has anything, advising the Outsider to be careful along the way.
The Forest of Magic
The Forest of Magic is slightly more dangerous than the fields he traveled beforehand. Not letting his guard down, and spotting a few fairies along the way, he finds Marisa at her house. Marisa greets the Outsider and asks how his journey has been going. They talk about his findings and Marisa tells him she'll help him if needed. With this offer in mind, the Outsider heads further into the forest, where he is told one of Marisa's friends lives, albeit keeping to herself. The Outsider discovers another house along the path, and meets a girl named Alice Margatroid, she knows him to be the Emissary and accuses him of stealing her dolls. Not willing to find out if he actually stole them or not, she attacks him. The Outsider defeats Alice and convinces her he didn't steal anything. He offers to go find them for her, and heads further into the forest, meeting three fairies, Luna Child, Star Sapphire, and Sunny Milk. The three reveal they stole the dolls as part of a prank, and tell him to shoo off. After defeating them, the Outsider retrieves the dolls and finds the mushroom Yuuka asked about earlier. Content with his work here, he decides to head back to the Garden of the Sun.
Return to the Garden of the Sun 1
The Outsider gives Yuuka the mushroom he found in the Forest of Magic, and asks her about the importance of his duty, as her tone changes drastically when speaking of it. She asks him if he knew of previous Emissaries, to which he responds Alice told of two who have a poor history in Gensokyo. Yuuka says the Outsider could become just like them. The Outsider deduces she speaks of the him and the others so poorly because of a far better Emissary in the past she respected. He insists he will become nothing like the previous two, and Yuuka laughs, saying the Outsider reminds her of the Emissary she respected. With not much else information to find, Yuuka tells the Outsider to go find a special flower found only in Misty Lake.
The Scarlet Devil Mansion
The Outsider goes back to Kourindou and north to traverse Misty Lake. Along the way he finds a fairy named Daiyousei, and she asks him about her friend Cirno not appearing for a while. She also tells him of a scary mansion north of the lake and the Outsider decides to investigate. He finds the special flower Yuuka asked for along the way and heads north to the Scarlet Devil Mansion. In his path is a gatekeeper named Hong Meiling. Meiling says she was ordered not to let him enter the mansion. After hearing this, the Outsider fights Meiling and heads inside the mansion to find out why.
The mansion is far bigger on the inside than on the outside. He goes from room to room ransacking them while finding keys to different rooms. One of which is the Chief Maid Sakuya Izayoi's room, where he finds a journal telling of him not being allowed to enter by her mistress, Remilia Scarlet. More eager to find out why, he heads to the upper floors and is stopped by Sakuya. Sakuya introduces herself shortly before battling the Outsider. The Outsider emerges victorious, and gives his word he only wishes to meet the mistress, not harm her. She reluctantly agrees, threatening to eliminate him if he tries anything.
The Outsider and Sakuya enter Remilia's room. The Outsider gets a dreadful feeling while meeting her, fearing he could be killed right then and there without anything he could do about it. He asks Remilia for the reason of stopping him, despite never meeting him, though he did break into the mansion, and decides to be careful. Remilia calls off and takes a look into his eyes only to find out he is unrelated to the previous Emissaries. Remilia, impatient with this turn of events, hands the Outsider the key to the basement to play with her sister.
The Outsider makes his way into the basement where he also feels a sense of dread. He finds multiple books and a journal about how this girl has been locked in the basement for a long time. Before long, Remilia's sister Flandre Scarlet entered the room and asked who he was. He explained he was sent down there by Remilia to play with her. She decides she wants to play Danmaku and brutally defeats the Outsider at it. The Outsider asks what happens to humans that end up in the Scarlet Devil Mansion, finding out from Flandre they get eaten, and sometimes blown up. The Outsider is shocked, and decides to head back to Remilia to question her about this. Remilia explains this happened a long time ago, and she lets humans go after she's done with them.
After speaking to Remilia, she tells him several keys are located around the mansion, and if he finds his way into the library to find a special book, she may tell him more of Remilia's past. With this in mind, the Outsider finds his way into Voile, the Great Library. With no way to tell where he's going, he finds a girl named Koakuma sorting books. With orders to capture strangers in the library, she does battle with him and loses. She agrees to bring him to her mistress, where he meets Patchouli Knowledge. Already familiar with him, she tells him to find an object in the Bamboo Forest of the Lost before giving him what he wants. With nowhere else to go, the Outsider decides to head to the Youkai Mountain before the forest.
The path to Youkai Mountain includes the reopened Myouren Temple along the way. Inside the Outsider meets Byakuren Hijiri, and she has been looking for him a while. Finding the Emissary, she tells him of what happened with the previous ones, recollecting them going on a rampage and killing many youkai, with almost no resistance due to the amount of powers they gained in their journey. It was because of this the rules for Emissaries were adjusted to guard Gensokyo. Byakuren offers her help and the Outsider heads towards Youkai Mountain.
After departing for Youkai Mountain, the Outsider immediately finds two Tengu of the mountain almost land on a girl in red clothing. Eavesdropping in plain sight, he finds out the two Tengu, Aya and Momiji Inubashiri are looking for him, and they head upwards. With this in mind, he heads up the mountain.
Before long, the Outsider finds Aya standing around a waterfall. After being asked several questions by her, he makes clear he knows what the point of her doing that is, and busts Momiji trying to sneak up behind him, declaring he will not go with them unless he is defeated in battle. With Aya holding back, and Momiji losing, they are told to go tell their lord to wait for him to come there. The Tengu left soon after, and the Outsider decides to go elsewhere before going further up the mountain.
Bamboo Forest of the Lost
The Outsider decides to head to the Bamboo Forest of the Lost after stopping at Youkai Mountain. At the entrance, he finds Mokou patrolling the area, and she begins to chide him for returning there. The Outsider is willing to fight Mokou to gain entrance despite her protests. She gives in and guides him into the forest without a fight.
During his exploration of the forest, the Outsider once again encounters Mystia, who has trained heavily since last because of his insulting her singing. After defeating her a second time, Mokou runs into them and acknowledges he is actually an Emissary, and challenges him to a fight. Though the Outsider won, he knew she was holding back due to her never-ending stamina. Mokou scolds him over Mystia's power growing because of him, and tells them to go on a journey together to make amends. The two are reluctant to do so, but he apologizes nonetheless. Mokou returns to the forest, and Mystia back to her lamprey stand.
Within the forest lies a building the Outsider finds. There he finds two girls with rabbit ears running an absurd amount of laps and complaining. Upon asking what's going on, a pink-haired women stops the Outsider mistaking him for someone else because of his voice. She detects he is the Emissary due to the "Impurities" he gives off, and he is trying to defuse the situation because of the extreme aura she lets off, as if he was facing Remilia again. Neither side could hit eachother during the battle, and are soon stopped by another women, Eirin Yagokoro, who chastises the pink-haired Watatsuki no Yorihime for challenging him in the first place regardless of what he intended. The two rabbits, Reisen Udonge Inaba and Reisen II, alongside everyone else head into the building to talk, where the Outsider also meets Watatsuki no Toyohime, Tewi Inaba, and Kaguya Houraisan. The Eientei has numerous conversations with him.
Reisen II talks about their training under Yorihime, and that she wishes to join him on his journey.
Reisen U.I cooks with the Outsider, holding him in his arms after falling over due to a self-inflicted injury. Yorihime and Eirin mistake this for her using her powers to seduce him, though she stands up to these allegations and calmly explains the situation.
Toyohime asks the Outsider what he plans to do at the end of his journey. He replies it's too early to decide what to do.
Yorihime tells the Outsider she could train him after he gains some more experience and brings back an object from Youkai Mountain.
Tewi talks with him about what they do at Eientei, and says she can provide some good luck.
Eirin also speaks with him about his journey and offers her assistance when necessary.
Kaguya is in her room with the Outsider where his clumsiness smashes his head through the wall where he finds the 5 treasures as part of the 5 impossible requests. Kaguya says finding those objects can lead to love and few have tried, though the Outsider believes they're only objects and can't do that, to which Kaguya agrees.
After having conversed with the entirety of Eientei, the Outsider decides he can go wherever he wants.
Middle Youkai Mountain
The Outsider goes up the mountain in hopes of finding something useful, like the object Yorihime tells him exists. Before he starts to scale the mountain, he is grabbed by a rubber hand dragging him towards the water. He breaks the hand, and Nitori Kawashiro hops outside the water, angered. She tells him to stop heading up the mountain, clearly not fond of his kind. Ignoring her warning, he heads up the mountain.
Partway through the mountain, he is surprised by Nitori again jumping out the water. She warns again she doesn't want to see him move up the mountain anymore, and even battles him for a while. Noticing how stubborn the Outsider is, she backs off and threatens him further.
The Outsider comes across three girls, one of which he saw almost get landed on earlier by Aya and Momiji. Shizuha and Minoriko, the Aki sisters, greet him along with Hina Kagiyama. After chatting a while Hina leaves, and Shizuha offers her assistance to the Outsider on his journey.
He finds an entrance to a cave between two parts of a waterfall, and Nitori appears out of it, prepared to stop him right there. In the middle of battle, the Outsider hears a voice telling him to use the Gem of Boundaries to attack. He uses Danmaku to Nitori's surprise, and Momiji steps out to stop them from fighting. Momiji and the Outsider convince Nitori to back off and let him climb. Momiji still has her duties to perform for the Great Tengu, and challenges the Outsider again. The Outsider agrees, and they duke it out one last time.