The fourth arc of A Certain Magical Index, consisting of volume 4 of the light novels and episodes 15-17 of the anime. This story arc was omitted from the manga for some reason, even through some important plot points happen here.
When word gets out that Touma defeated Accelerator, several people start challenging him to fights, thinking if they can beat him, they can claim Accelerator's title of the #1 esper. Komoe tells him to leave the city for a while until Academy City's higher ups pull enough strings to make the heat die down. Touma agrees and decides to go to a hotel near the beach and meet up with his parents. Index wants to go too. He reminds her that she's supposed to keep a low profile because she's technically an illegal immigrant, but she insists. They take a taxi and he's nervous as they are stopped at the city gates, but to his surprise, Index is in the database (which confirms "Index Librorum Prohibitorum" is her legal name) and they are waved on.They arrive at the hotel and are the only guests. His parents and young cousin will arrive tomorrow morning. Touma and Index play at the beach. Index picks up a washed up jellyfish and drops it on him, not knowing what it was and thinking it was some kind of toy. Touma curses his bad luck and treats his stings with a cream. Later, they take a bath at the onsen, which is separated into girl's and boy's sides by a wall, and she asks him what his parents are like. To cover the fact that he has no memory of them, he tells her to treat it as a surprise, which annoys her. They go to their room and turn on the TV, but it plays a porno, leading her to call him a pervert and bite him, ignoring his protests of innocence. Touma muses that tomorrow, he will finally meet his parents for the "first" time, and goes to sleep.Note: In the light novel, Touma and Index just go straight to the hotel and go to sleep.
The next morning Touma wakes up and goes outside. He meets a man who introduces himself as Toya Kamijou, his father. Toya asks him why he's acting like he didn't recognize him, and Touma covers up by saying he hasn't seen him in so long. Toya says Touma's mother and cousin are coming up, but Touma is shocked when Mikoto Misaka walks up, wearing a dress and sandals instead of her regular outfit. He asks her what she is doing here, but she gets confused and claims she is Otohime Tatsugami, his cousin. Touma asks his father how he knows Mikoto, but Toya doesn't know what he is talking about and says she is Otohime. Then Index walks up, wearing a dress and hat. Touma asks her how she got there when he left her in their room, but she gets confused and Toya tells him to stop disrespecting his mother, Shina Kamijou. Touma asks if this is some kind of prank, but the three have no idea what he is talking about. He gets annoyed and goes back inside, but finds that the two hotel employees have been replaced by Misaka 10032 and Stiyl Magnus. Then Pierce Aogami appears, wearing Index's outfit, and Touma screams in pure horror.The family decides to spend time at the beach. Otohime jumps in the water and asks Touma to join her, but he declines, still weirded out. Then Shina comes out wearing an incredibly revealing swimsuit, and Toya's eyes light up in delight. Touma, still seeing her as Index and thinking this is some kind of prank, angrily strangles his father and accuses him of being a pedophile. Then Index comes out wearing her swimsuit, and Touma can barely stop from throwing up upon seeing the horror of Pierce Aogami in a girl's swimsuit. He buries "Pierce" in the sand and runs away.
Touma goes back in the hotel and is flabbergasted to see on the news that Heaven Canceler and Komoe have replaced two reporters, and that Kuroko Shirai has replaced Barack Obama (she even says, "Yes. We. Can!"). Realizing this is too elaborate to be a mere prank, he runs into town and finds seemingly everybody has swapped roles (highlights include a little boy as a police officer, some fat men wearing midriff-baring women's clothes, an old man reading a Shakugan no Shana manga and acting like a child, and several people of various ages wearing school uniforms). Otohime catches up to him, shows a picture of the two of them at a New Year's party from her cellphone, and asks if he remembers her now. Of course he doesn't, but he finally sees that she sincerely thinks she is Otohime, and that she doesn't notice that she looks like Mikoto and not like her picture.Note: In the light novel, Touma meets Otohime (who jumps on him in his bed) before his father, and he sees the news before they go to the beach.
Touma walks around, wondering how everyone switched bodies and why he's the only one who notices. He notices a girl wearing sexy bondage gear with a red nun's habit over it, with her bangs covering her eyes, and tries to walk around her, thinking she's just another switched person, but she suddenly holds a saw to his throat and demands to know if he is the one who caused this. Kaori Kanzaki and Motoharu Tsuchimikado run up and ask her to stand down. Touma asks what is going on, but the three ignore him and talk amongst themselves. Motoharu notes that Touma sees him and Kaori as themselves and not as other people. Kaori introduces herself to the girl as a member of Necessarius. The girl introduces herself as Misha Croitsef, a member of Annihilatus, a magic organization that works for the Russian Orthodox Church, and says she is trying to determine if Touma is the culprit. Kaori says it is unreasonable to accuse him and says that though their organizations don't normally interact, they should work together, and Misha agrees. Touma has enough and demands to know what is going on. Kaori says his attitude hasn't changed. He inwardly realizes she's an old acquaintance of his, and is glad that she hasn't noticed that he doesn't remember her.Kaori and the others explain that someone has cast a spell called Angel Fall, which quite literally caused an angel to fall out of Heaven and to Earth. This has caused great disturbances, including everyone in the world switching bodies. They don't know who the caster was, but all signs indicate he or she is somewhere in this town, and they were trying to find this person to reverse the spell and return everything back to normal. They suspect that the caster did this in an attempt to take the angel's place in Heaven, citing how according to Kabbalah, the ranks in Heaven are full, and humans can only ascend by taking the original inhabitant's places. Since Touma wasn't affected by the body swapping, Misha pegged him as the most likely suspect. Kaori points out Touma has no knowledge of how to use magic and has no injuries that an esper would have from using magic. Motoharu adds that the reason Touma wasn't affected is because of his Imagine Breaker, and he briefly explains Imagine Breaker to Misha. Touma is shocked that he knows about it. Misha suddenly blasts Touma with a massive column of water. Touma blocks it with his right hand, and it splatters apart without harming him or even getting him wet. Misha says she was testing if Imagine Breaker was real, and she now believes Touma is innocent, apologizing for attacking him earlier. Touma incredulously asks Motoharu how he knows about Imagine Breaker and what he is doing with Kaori, and he reveals he is a member of Necessarius too.Motoharu says he was originally from the Magic Side, but he was assigned a few years ago to go undercover in Academy City as a student. As a result, he knows a lot about what goes on there, including about Touma's adventures. He adds that he went through the Power Curriculum and gained an esper power from it, so he can no longer use his magic like he used to without taking damage. He explains how magic works, a principle that is opposite how esper powers work. While espers use their Personal Reality to change the world, magicians borrow power by emulating various magical beings like angels or mythological figures, which is called Idol Theory. The more perfect the emulation, the more power you can borrow. Getting back to the present, Motoharu, Kaori, and Misha explain that they detected Angel Fall going off and took steps to protect themselves, which is why Touma sees them as themselves and they see each other as themselves. However, the protection wasn't perfect, so everybody else sees them as someone else. Everyone sees Motoharu as the actor Hajime Hitotsui, which forces him to stay hidden lest he be mobbed by Hajime's fangirls. Everyone sees Kaori as Stiyl Magnus. Misha doesn't say who everyone sees her as.
Kaori and Misha decide to join Touma for dinner with his family and Index, introducing themselves as friends of Touma, while Motoharu stays hidden. The others apparently see Misha as a cute girl. Kaori gets annoyed that the others keep addressing her as a guy. Later, Touma meets Motoharu, who opens his shirt to show several still-healing injuries, and warns that the spell he cast to protect him from Angel Fall took a lot out of him, and he might die if he uses magic again so soon. He also warns Touma to not complain about his bad luck around Kaori. He explains that Kaori is a Saint, a person born with a physically perfect body similar to the Son of God. This gives her incredible strength, speed, toughness, and magical potential, as well as overwhelming good luck. However, Kaori hates her good luck because it only protects her and not the people around her. She's had to watch many people suffer and die while she was unharmed. As result, talking about luck is a really touchy subject for her.Kaori meets Touma and says she wants to take a bath. Since everyone else thinks she is a guy, she can't use the girl's bath, so she's using the men's bath and orders him to guard the door. After a few minutes, Toya walks up and asks him to take a bath with him as father and son like old times. Touma says it is occupied, but Toya says that doesn't matter, they're all guys here. Touma tries to tell him it's not a good idea, but his father grabs him and drags him in. Touma gawks as he sees Kaori's perfect body in its full glory, but Toya sees a man's body so it's nothing special to him. Enraged, she pulls out her sword and attacks them, forcing them to run away. She angrily gets dressed and tells Motoharu that Touma is useless. However, Motoharu scolds her and says she owes Touma everything for saving Index, yet she never did anything to repay him, so in his opinion, Touma deserved to see her naked.Touma and his father stop to catch their breath, and Toya is confused why that "guy" got so embarrassed about being seen by them, and concludes that "he" was gay, quickly adding that he doesn't think there's anything wrong with that. Touma suddenly realizes that because of Angel Fall, this person before him isn't what his father actually looks like. While he's thinking, Toya says fondly that his expression makes him resemble his mother. They look up and see Misha standing alone. Toya encourages his son to talk to her, joking that if he plays his cards right, he might even get her to go out with him.Touma walks up and tries to start a conversation, but Misha ignores him. He offers some gum and she finally acknowledges his presence, saying she likes sweet things because they remind her of the grace of God. She takes the gum, strangely nervous and careful to not touch his right hand. He asks her what she knows about Angel Fall, and she says they should find a way to end it soon, because the angel that fell will want to go back to Heaven soon, and angels are among the most powerful and destructive beings in existence. Once it runs out of patience, things won't be pretty.Touma goes back to the hotel and overhears Toya and Shina in their room, about to have sex. Since Shina is still in Index's body, Touma quickly barges in and asks his parents if he can sleep in their bed. Shina agrees, while Toya growls but has no choice but to accept her decision.The next day, Shina panics and says she realizes she forgot to lock the door of their house, and she can't rest until she goes back and corrects this. Misha volunteers to go with her on the train back to the Kamijou family's hometown, which Shina delightedly accepts. As they leave, Toya jokes that Misha must be trying to score points with her future mother-in-law and asks Touma when they should have the wedding. Touma tells him to cut it out, but he remembers how Misha was so nervous last night and wouldn't touch his right hand. He voices his suspicions to Kaori and Motoharu, and they suspect that Misha was the one who cast Angel Fall and she didn't want to touch Imagine Breaker so the spell wouldn't be broken.
Fearing that Shina may be in danger, Touma and Motoharu take a taxi to the Kamijou Residence (apparently, Motoharu's sunglasses are enough to stop people from "recognizing" him as the actor). They arrive at the house first and enter. Inside, they find the house is loaded with various trinkets from all over the world, and Motoharu warns Touma not to touch anything. Touma finds his baby pictures and is overjoyed to finally learn what his mother looks like. However, his father looks the same in the picture as he does now. Motoharu says Toya wasn't affected by the body swap, which may mean he was the one who cast Angel Fall. At this moment, Shina and Misha enter. Misha sees the picture and runs off. Motoharu tries to follow her, but Shina grabs him, screaming in excitement and asking "Hajime Hitotsui" what he is doing in her house, saying she is his biggest fan. Unable to free himself from her grasp, he tells Touma to go on ahead and stop Misha, for she will most likely try to kill Toya, since killing the caster is often the simplest way to end a spell. Touma runs out, wondering if his father has really gotten involved with the Magic Side. He manages to persuade a trucker (who has switched bodies with Aisa Himegami) to give him a lift back to the hotel.Note: In the light novel, the events leading up to this scene are vastly different. Kaori is the one who attacks Touma accusing him of being the one who cast Angel Fall before Motoharu stops her. Even then, she forces Touma to strip to prove that he didn't get any injuries from casting magic. He gets really embarrassed, yet she gets pissed at his reaction and calls him a pervert. Instead of Toya dragging him into the bath, Shina and Otohime shove him in, saying he was stinky and should take a bath. When Touma runs away after seeing Kaori naked and getting attacked by her sword, he suddenly gets attacked by the notorious Serial Killer Jinsaku Hino. Misha shows up for the first time and helps drive him off. After they introduce themselves and agree to work together, they suspect that Jinsaku was the one who cast Angel Fall because he kept muttering something about an angel and he looked the same as his mug shot from the news. The morning after the incident when Touma interrupted his parents in their room, Touma, Motoharu, Kaori, and Misha go on Jinsaku's trail, using the people-clearing field to prevent the police and bystanders from interfering. During this time, Touma offers Misha gum and she nervously accepts it while avoiding his right hand. After a huge cat-and-mouse game that crosses cities, they finally manage to capture him when he takes shelter in the Kamijou Residence. However, when they interrogate him about Angel Fall, he has no idea what they are talking about. They realize that he was muttering about an angel because he's nuts and hallucinates, and that he has split personalities and the Angel Fall made the personalities switch. They then find the family photos and Misha concludes from them that Toya was the caster and rushes out to get back and kill him. Touma goes after her while Kaori and Motoharu take Jinsaku and leave him tied up near the police station.Touma arrives at the hotel and confronts his father at the beach. Toya asks where he has been and Touma says he was back at their house and knows that he has gotten involved with the occult. Touma demands an explanation. Toya's gaze softens and he says he did it for him. He reminds Touma (though Touma's learning about this for the first time because of his amnesia) about how ever since he was little, he was extremely unlucky. Everywhere he went, misfortune followed. Soon everyone blamed Touma for anything that went wrong, and a grown man who went bankrupt called little Touma a demon and tried to stab him with a knife. Fearing for their son's life, Toya and Shina sent him to live in Academy City as soon as he finished kindergarten. However, even though Academy City is supposed to embrace science and wipe away superstition, Touma was still shunned. Toya then began collecting as many lucky trinkets as he could, hoping they could somehow counteract Touma's misfortune. Touma says he shouldn't have done that, and that he can shoulder his misfortune on his own. Toya accepts and says he'll stop collecting trinkets, realizing he was falling into the same superstitions that the crazy people who hated little Touma did. Surprised, Touma asks his father if he was the one who cast Angel Fall, but Toya has no idea what that means.
Suddenly, Misha appears and draws her weapons, advancing toward Toya. Touma begs her to stop and that there has been some kind of mistake, but she doesn't listen. Kaori appears and says she's figured it out. She called Annihilatus and they don't have anybody named Misha Croitsef, but they have a Sasha Croitsef who matches Misha's description. Suddenly, the daytime sky turns to night, with a full moon. Misha gathers water from the ocean and it crystallizes into wings on her back. Kaori says she is the angel who Angel Fall made fall out of Heaven, who took over Sasha Croitsef's body. She is Archangel Gabriel, The Power of God. Just like she warned earlier, her patience has run out and she wants to go home, no matter what it takes. Gabriel casts a spell and the sky lights up with geometric patterns. Kaori says this is The Sweep, the same spell that destroyed Sodom and Gomorrah, and it will activate in roughly half an hour, wiping out the city. Touma prepares to fight, but Kaori tells him to figure out how to stop Angel Fall while she keeps Gabriel busy, for once the spell is stopped, Gabriel will be returned to Heaven and The Sweep will be cancelled. Touma reluctantly agrees, grabs Toya, and runs. Gabriel tries to follow, but Kaori draws her sword and declares her magic name: Salvare000 - Be The Salvation of Those Who Cannot Be Saved. She says that normally, even as a Saint, she would have no chance against an angel, but she is not limited to Christian magic. She also has Shinto magic, and in Shintoism, humans can kill deities. They clash and Kaori charges her sword with magic so it can injure Gabriel, but it soon becomes clear that Kaori is outmatched and can only stall the archangel.Touma and Toya run into the hotel to find everybody unconscious. Toya asks what is going on. Touma tells him to quit playing innocent and end Angel Fall already, but Toya still doesn't understand what that means. Motoharu appears and says that Toya was indeed the one who cast Angel Fall, but by a complete coincidence. Each trinket Toya collected was useless on its own, but all of them strategically placed in the house according to the principles of Feng Shui ended up combining their power to create an effect based on Idol Theory, which ended up being Angel Fall. As Touma struggles to digest this and Toya wonders what this "actor" is doing here, Motoharu says he told Touma not to touch anything because to disturb the site now may cause disastrous effects. Right now, there are only two ways to end Angel Fall, destroy the spellcasting site in a single blow, or kill the spellcaster. Since he can't use magic right now, there is only one option. He cracks his knuckles and advances toward Toya.
Touma tries to tell him there has to be some other way, but he says there isn't. Touma tries to defend his father, but Motoharu reveals he is an elite martial artist with training and experience vastly superior to Touma's self-taught street-fighting skills. He effortlessly beats Touma into the ground, with Touma unable to land a single hit. Toya tries to help his son, but gets knocked out with a single punch. Touma's injuries are so bad he can't move. Motoharu then apologizes and says he's decided to use magic to destroy the spellcasting site, sacrificing himself to save the world. Touma begs him to stop, there has to be some other way, but Motoharu says he's too naive. He casts a spell and seems to explode in a geyser of blood. The spell releases a massive beam of light that arcs through the sky and annihilates the Kamijou Residence. As soon as this happens, Gabriel disappears, the sky goes back to normal, and Angel Fall and The Sweep are cancelled. Kaori collapses in relief, commenting that her strength had almost run out and she would have died if the fight had gone on any longer.Touma wakes up back in his usual hospital room in Academy City. He becomes sad about Motoharu's sacrifice, only for Motoharu to walk up, alive and well. As Touma is flabbergasted, Motoharu reveals that the esper ability he gained from the Power Curriculum was Auto-Rebirth, which allows him to heal from injuries. He's considered a Level 0 because it works too slowly to matter in a fight and doesn't stop pain, but it allows him to just barely survive the damage of using magic while an esper. Touma angrily asks why he didn't explain this earlier and pretended to sacrifice himself, and Motoharu says he lies all the time because it amuses him. When he said he was a student of Academy City, he lied. When he said he was a member of Necessarius, he lied. He's really a Double Reverse Quadruple Agent, an ultimate Wild Card who plays all the sides on a whim. He leaves, and Touma is really annoyed.
Touma's parents come in and ask how he is doing, and he is relieved to see that Shina is back in her original body. He tells her he's gotten used to being in here, but she scolds him and says that getting injured is not something to get used to. His father says he's just glad he is all right. Apparently, their memories have been modified, as they don't seem to remember all the crazy things that happened and think Touma injured himself in an accident. They also think their house was destroyed by a random gas leak explosion. They tell their son not to worry about that, as they have more than enough money saved to get it repaired.Touma's relief is short-lived when an angry Index enters. She talks about how Touma kept snubbing or even pushing her around during the vacation. Of course, this is because he was disgusted by seeing Pierce Aogami in her clothes, but he can't tell her that. She bites him, and his screams about his misfortune echo through the sky.