In the aftermath of the incident involving Oriana's Shorthand, Fukiyose Seiri recovers in a hospital room. Deep inside, she feels bitter upon the thought of ruining everyone's fun in the Daihasei Festival because of her condition, which she has been thinking was just a heat stroke. Soon, she is accompanied by a certain frog-faced doctor, who assures her that he will be able to help her.
Meanwhile, Stiyl impatiently waits at the bus terminal with an All-Around Reality Circle prepared. He soon receives a call from Tsuchimikado Motoharu reporting Touma's destruction of Oriana's Shorthand and asking him to perform the All-Around Reality Circle spell once again. Motoharu also reports to him about the incident that ended with Touma destroying the Shorthand and the only casualty.
With the call ended by Stiyl he prepares for the spell, and traces Oriana's location: Futsuka Station in District 7.
Touma and Motoharu rush to pursue Oriana once again, and with Stiyl's help, they track down Oriana's movements. Oriana takes them to different locations, trying to wear them down, and makes her escape by boarding one of the buses roaming around Academy City. They failed to make it in time, but upon Touma's confirmation that no one else is aboard the bus, Motoharu contacts Stiyl and the rune magician activates one of his runes at the bus. It turns out that Stiyl prepares runes on all the buses they found at the terminal earlier.
The explosion brought by the rune tips the bus to one side and turns it into an inferno. However, Oriana makes it out in one piece, using a water spell to douse the flames. Touma confronts her about Seiri's involvement, and Oriana reveals that she expects it to happen; according to her, everyone is involved, and it would be easy for one to be dragged into the conflict.
With the intent to finish off Touma, Oriana unleashes her Shorthand, but it only affected Motoharu. Oriana tells him that the spell uses blue letters (attributed to water) to cancel the effects of regeneration (attributed to fire). Touma tries to cancel the spell, but he finds out that it is a sustained spell. Oriana then advises Touma to get to her quickly so that he can save Motoharu.
Touma rushes to Oriana while she prepares an ice wall to act as a diversion. Touma breaks through the ice, but faces a vortex of wind coming straight at him. Although slightly wounded by the vortex, he manages to dispel it; Oriana, though has another spell prepared for him: a sword made out of shadows. Oriana throws this to Touma, and watches as it explodes, throwing Touma off-balance. Oriana continues on her relentless streak of hitting Touma on the chin and in the stomach with the spells on her hand, and confidently comments on Touma's inability to stand up after her attacks.
However, Touma proves her comment wrong.
Oriana threatens Touma with Blade Crater, a spell which "would kill him if he moves", but this did not move Touma; instead, he keeps on stepping on the spell area. Oriana is forced to activate the spell prematurely, but Touma rushes to her in response, breaking through every defense she makes, and lands a punch in her face. The hit throws Oriana back, making her lose grasp of the package she was holding.
Oriana soon stands, even teasing Touma with her breasts, and escapes, leaving Touma with her package. She then assures him that her spell would wear off after 20 minutes.
As Motoharu recovers, Touma takes the time to examine the package Oriana is holding. He is shocked to find out that it does not contain Stab Sword; instead, an ice cream shop sign is the thing Oriana has been carrying all along.
Meanwhile, Oriana undresses elsewhere as she talks to someone using a spell card, who is clearly worried about what happened to her. Oriana guarantees that everything is fine, despite the fact that someone else has already gotten the billboard.
On the other side of the world, Laura Stuart receives a shocking development from Charles Conder, the curator of the British Museum: the weapon called as Stab Sword does not exist. Charles explains that the tale behind Stab Sword is a tale that spiraled out of control and that the true identity of the sword is the Cross of St. Peter (Italian: Croce di Pietro), the cross used to crucify one of the Twelve Apostles.
Laura is alarmed by the new information; she realizes that when the trade is fulfilled, Academy City will cease to exist.
Laura relayed the information to Stiyl, who then hands out the information to Touma and Motoharu. Although Touma has no idea what happens when Academy City is put into the dominion of the Roman Catholic Church, Stiyl explains that it will tip the balance between science and magic to the favor of the Church, a fate worse than mere destruction.
Later, Touma ponders on what Stiyl says, while he is seen by Index at the park. Index is ignored by Touma at first, but she manages to get his attention. Touma is shocked that Index is wearing a cheerleader's outfit, and his reaction caused a misunderstanding that earned him a punch on his head.
Index is actually concerned about Touma and wants to cheer him up, but Touma exposes that he thought that she is angry because she is hungry. That infuriated Index and she hits him hard on his head.
Meanwhile, Touma's parents Shiina and Touya meet Misaka Misuzu once again; this time, she is accompanied by her daughter Mikoto. Misuzu wants to introduce Mikoto to the "family of the one she likes", much to Mikoto's shock, and invites them to lunch together. Soon, a certain scantily-clothed blonde lady bumps into Touya, and after the lady leaves an apology, Touya has to apologize to Shiina for fixing his eyes too much on the lady.
Soon, the Misakas and the Kamijous meet up at a nearby restaurant; Touma and Index also arrive as well. Mikoto displays an outburst for not being able to find Touma anywhere, and even drags Index into the discussion. Touya soon exposes that Index has accompanied Touma in a beach one time, much to Mikoto's shock. Index soon becomes curious about Mikoto, asking her if she is Touma's girlfriend, and before a commotion could start, Misuzu invites everyone for lunch to start.
Touma soon wonders if Misuzu is Mikoto's sister; Misuzu introduces herself as Mikoto's mother, which shocks both Index and Touma.
- Touma and Motoharu confront Oriana Thomson, with successfully engaging her in combat long enough for her to abandon her package, the Stab Sword, which is fake.
- The Stab Sword is revealed to be non-existent, to cover the identity of St. Peter's Cross.
- Lidvia's true plans are revealed; which is to use St. Peter's Cross to take control of Academy City.
- Touma meets Misaka Misuzu, while Mikoto meets Touma's parents.
By order of appearance
- Fukiyose Seiri
- Kamijou Touma
- Tsuchimikado Motoharu
- Misaka Mikoto
- Heaven Canceler
- Stiyl Magnus
- Oriana Thomson
- Lidvia Lorenzetti (voice-only)
- Laura Stuart
- Kamijou Touya
- Kamijou Shiina
- Misaka Misuzu
- All-around Reality Circle - Tsuchimikado Motoharu, Stiyl Magnus
- Fire magic - Stiyl Magnus
- Rune magic - Stiyl Magnus
- Shorthand - Oriana Thomson
No new abilities were introduced during this episode.
- Academy City
- Minamizawa Middle School (flashback-only)
- The hospital Heaven Canceler works in
- Automated Bus Maintenance Terminal
- St. George's Cathedral
- Futsuka Station
- Oriana wears her signature clothes for the first time in this episode.
- Oriana cannot use the same spell twice in her lifetime, due to the nature of her Shorthand grimoires. This explanation was excluded in the anime adaption but was included in the Light Novels.
- Seiri's flashback references Touma's worried look from the previous episode.
- Touma references the scene back in episode 8 where Touma sees Index with her cheerleading outfit for the first time.
- Touma's parents references Index being with Touma at the beach, which happened back in episode 15 of the first season.
- The episode references St. Peter, one of the Twelve Apostles of Jesus, and is central in the establishment of Roman Catholicism, and is often considered the Pope of the Church.
- St. Peter's Cross is an inverted Latin cross. According to tradition, Peter requested for him to be crucified in an inverted manner during his crucifixion, as he was unworthy of being crucified in the same manner as of Jesus Christ (upright).
- Touma's cut on his face, changes size, position as well as angle, several times during the course of the episode.
- The scene where Stiyl is walking and talking to Touma for the first time, after acquiring the covered-up billboard from Oriana, has the phone that Stiyl is supposedly using during that scene is clearly missing.
- During the scene where Stiyl, Touma and Motoharu are resting at a cafe, there is a sign written in english on a chalkboard, though the last word is misspelled.
- During the scenes of jealousy for both, Index and Shiina, a dark aura animation effect is used on them.
- The scene where Touma meets up with his parents in the restaurant, Touya and Shiina's legs are notably missing under the table. Another scene where Mikoto argues with Touma, a female background character can be seen sporting a sports uniform, however, when the scene is revisited where Index argues with Mikoto, the girl sports a totally different attire altogether; in fact, it was the original attire worn by the girl when Touma entered the restaurant.
- Where is the true St. Peter's Cross?
- What is the power of St. Peter's Cross?
- What do the Roman Catholics gain from using the St.Peter's Cross?
- Seiri: "Can you help me?" -said to the Heaven Canceler.
- Heaven Canceler: "Just who do you think I am?" -response to Seiri's question.
- Touma: "Damn you. I don't know what that Stab Sword is worth to you. I don't know if it's going to change history or alter the world in some grand way. But hurting people just to get your hands on it is wrong! If it does nothing more than cause meaningless violence, then I will destroy it with this hand!" -said to Oriana.
- Touma: "Who the hell cares about something like that? All the effort Fukiyose put into making Daihasei Festival a success is being rendered meaningless! Do you think I'll just sit idly and let you do this? That isn't good enough for Kamijou Touma!" -said to Oriana.
- Oriana: "Don't think our little game is over just yet. I'll be turning up the heat from now on." -said to Oriana.
- Oriana: "I won't let anyway get in our way, not like anyone can."- said to Lidvia