"Ambush" (伏兵 Fukuhei?) is the 45th chapter of the Toaru Kagaku no Railgun manga series.
After the three-legged race, Mikoto meets up with Saten and Uiharu. Mikoto notes that her clothes are dirty and she'll need to get new ones. Saten praises Mikoto's speed and an unknown voice says that Mikoto has been fast since she was in kindergarten. It is Mikoto's mother Misuzu, visiting the city. Saten and Uiharu are amazed at how youthful she is, and the former also comments on how she resembles Mikoto except for having larger breasts. Mikoto then worries about whether she can get new clothes in time for the next event. Saten suggests asking someone to take her place, but Mikoto doesn't feel like doing so because of her eventual showdown with "him" (Kamijou Touma). Misuzu hears this and excitedly asks what she means by "him", then talks with Saten and Uiharu about "him". Mikoto is mortified.
Meanwhile, Misaka 10032 watches the festival on a screen while holding her cat. She comments that she can't participate (due to not attending any school) and heads back to the hospital.
Awatsuki Maaya and Wannai Kinuho watch a tug-of-war event and are amazed at the intensity of the competitors. Kinuho asks Maaya if she's ever been in a fight. As they leave the event they talk about their lack of fighting spirit or experience in fights. Kinuho asks Maaya to get angry at her, something Maaya struggles with. They approach the next event and overhear other students declaring their intent to beat Tokiwadai Middle School. Kongou Mitsuko arrives, along with other Tokiwadai students, and declares that their school won't lose to just anyone. Kongou leads the others in a cheering session. Kinuho and Maaya hear from a nearby student that Mikoto is nowhere to be found. Kinuho searches around and finds Misaka 10032, mistaking her for Mikoto. She makes her participate in the event and lends her spare uniform (since 10032 is wearing the school uniform). The real Mikoto hurries to the event (passing over Oriana Thomson in the process) only to find 10032 in her place. Confused, she hides.
The event begins: Balloon Hunter, in which the goal is to pop the balloons on the opposing team's heads using specific balls, with anyone whose balloon is popped being eliminated. The non-Tokiwadai team immediately scatters, with one member claiming that their plan is for them to all survive so the event ends in a draw. The Tokiwadai team chases after them, with 10032 left behind and futilely trying to advise them to be more careful. Kirifu Megumi, one of the Tokiwadai competitors, spots Omoshi of the opposing team and pursues him. Omoshi seemingly levitates a ball with telekinesis and tries to hit Megumi's balloon. Megumi stops the ball, revealing that she's a better telekinetic, and uses many balls to attack Omoshi and pop his balloon. Megumi is confident in her victory but her balloon is suddenly popped by a ball, causing her to be eliminated. She protests that Omoshi cheated, but Omoshi reveals that the ball had been controlled by one of his teammates hiding in the bushes (he is actually a Level 0). He calls Megumi by her name and explains that his team, due to being lower level espers, researched their opponents.
In order of appearance:
- Misaka 10032
- Misaka 10032's cat
- Awatsuki Maaya
- Wannai Kinuho
- Kongou Mitsuko
- Misaka Mikoto
- Kirifu Megumi
- Electromaster (Railgun-variant) - Misaka Mikoto, Level 5
- Telekinesis - Kirifu Megumi, Level 4, and an unnamed female student (Level unknown, presumably less than 4)
- The entire scene with Mikoto, Uiharu, and Saten meeting Misaka Misuzu was originally part of chaper 44 in the magazine release, but later appended to this chapter for the tankobon release.