"Rainbow's End" is the 42nd chapter of the Toaru Kagaku no Railgun manga series.
At Sakugawa Middle School, Saten Ruiko is talking with her friends Mako, Muu and Akemi. She notices Uiharu Kazari looking sad. The two of them leave the school and, after confirming that Uiharu doesn't have Judgment work today, Saten spots a huge rainbow and suggests that they try to find its end. She claims that those who reach a rainbow's end will become happy, according to an urban legends site she found.
While searching for the rainbow's end, they pass by a florist's and Saten asks Uiharu about the meanings of various flowers. Then Saten spots a yellow balloon decorated with flowers and comments that it goes along nicely with Uiharu today. Uiharu is embarrassed as she realises that Saten had secretly flipped up her skirt to see her panties earlier.
The two girls spend the day casually having fun, playing with a pet dog and eating ice cream. Eventually they pass by Fukiyose Seiri and Himegami Aisa, who are discussing the future closure of a road for the Daihaseisai. They then cross a bridge and Saten spots a hill where they can see the rainbow's end, so they hurry there.
Along the way is a long staircase. Saten suggests they bunny-jump all the way up the stairs, but trips over and falls to the side of the stairs. They end up running up the stairs normally. Uiharu becomes tired and nearly loses her balance, only for Saten to give her a helping hand. Saten reveals that she knows about Uiharu doing daily training (to make up for her poor athletic skills) and always thinking first about the people of the city, and Misaka Mikoto and Shirai Kuroko know as well.
Finally they reach the top of the hill, but the rainbow has already disappeared. Saten's friends happen to be here as well. Muu points out that Saten has lost her hairpin and starts playing around with her hair. Uiharu smiles at this sight, causing Akemi to comment on how she's cheered up. It turns out that Saten was worried about Uiharu, who had become depressed when a fellow Judgment member became injured (which Uiharu thinks was due to her own lack of awareness). Uiharu gives Saten one of the flowers from her own hairpiece as a replacement for the hairpin. She says the flower is aster peacock and claims its meaning is "Tomorrow will be a full-team home run", which Saten's friends point out is clearly made-up.
In order of appearance:
No abilities were used in this chapter.
- Continuing with the running joke of her being a character that doesn't stand out, Aisa's entire face is conveniently covered throughout her entire appearance in this chapter.
- Uiharu's dorm and Saten's dorm are located in the opposite direction.
- Saten talking about her jeans from England is a reference to her being mentioned by the Jeans Shop Owner in Toaru Majutsu no Index SS: Kanzaki.
- A girl who was heading to a scene with Uiharu's navigation got really hurt while on Judgment duty. It is a reference of Tree Diagram Remnant Arc.