Sister's noise

"sister's noise" is the first opening theme for the second season of the Toaru Kagaku no Railgun anime series, Toaru Kagaku no Railgun S, and single by fripSide that was released on May 8, 2013. It is also used as background music in Toaru Kagaku no Railgun S Episode 24.

Promotional Video
The video for "sister's noise" adopted the concept of the Sisters, using them as background characters and as dancers who perform alongside the duo of fripSide. fripSide is featured in the video as they walk across an industrial complex, where they witness the sabotage of a certain laboratory where living beings who look closely alike were possibly made. Despite the attack, the facility manages to create two more clones, which look like middle-aged twins with a rotund build.

The promotional video was shot amidst cold weather conditions (one night's temperature was 3 degrees Celsius), requiring the cast members to wear jackets and thick clothing as soon as a scene is finished shooting. Both Yaginuma and Nanjo agreed that the dancers who performed as the Sisters contributed the most during the shooting.

Tracklist
The opening for Toaru Kagaku no Railgun S was written, composed and arranged by Satoshi Yaginuma and sung by Yoshino Nanjo under their band name fripSide.

The single release features the full version of the song.
 * 1) "sister's noise" - 1:30 (TV version)
 * 2) "I'm believing you"
 * 3) "sister's noise" -instrumental-
 * 4) "I'm believing you" -instrumental

Characters
By appearance
 * Misaka Mikoto
 * Shirai Kuroko
 * Saten Ruiko
 * Uiharu Kazari
 * Kamijou Touma
 * Frenda Seivelun
 * Takitsubo Rikou
 * Kinuhata Saiai
 * Mugino Shizuri
 * Accelerator
 * Nunotaba Shinobu
 * Misaka Sister
 * Haruue Erii
 * Konori Mii
 * Kongou Mitsuko
 * Wannai Kinuho
 * Awatsuki Maaya
 * Shokuhou Misaki

Spoilers

 * Mikoto battling Frenda Seivelun and Mugino Shizuri.

Trivia

 * Sister’s noise is probably short for Sisters' Radio Noise.
 * The opening video contains the most Level 5s in any opening video of the Toaru Majutsu no Index animated adaptations alongside dual existence.