Toaru Kagaku no Railgun SS3 is a side-story which is to be released in parts with limited edition DVDs and Blu-rays for the Toaru Majutsu no Index III anime. The story will apparently be as long as two regular volumes.
When Mikoto hears about it, she suspects the girl was sent by Shokuhou's clique as part of a harassment proxy war, so they accept the challenge. The challenge is a violin competition with the other side having a Stativarius, which go for more than a hundred million yen.
They need knowledge to defeat money, so with Uiharu and Saten's help, they are forced to figure out the secrets of that famous violin's sound and what the minute differences between them are. And during this thorough enemy observation, they learn how skilled Sakibasu is.
What is the surprising move that overturns everything for Kuroko!? This small conflict over violins is only the prelude to an incident involving many different forms of desire.
- "Stativarius" is a pun on the real-life Stradivarius, the legendary string instruments built by the Italian family Stradivari during the 17th and 18th centuries, known worldwide.