Episodes 12–17 of Dies Irae released exclusively on the web.

Touma Kamijou can't catch a break. After the invasion of Academy City, political tensions continue to rise as both the science and magic factions collide head on. It appears that Academy City intends to declare war against the Roman Catholic Church, consequently plunging the whole world into global warfare. Touma soon finds himself on the front lines once again, striving to protect his friends and allies.

Toaru Majutsu no Index III serves as the last installment of the original franchise as Touma, Accelerator, and the true Level 0 Shiage Hamazura continue their separate journeys, leading up to the final act of the original light novel series.

[Written by MAL Rewrite]

Long, long ago, there existed a world of magic and science. God, afraid of man's potential, split the world in to the world of science, Elde, and the world of magic, Fandavale. One day in Fandavale, a terrible witch named Cendrillon (Cinderella) revives. Cendrillon plots to rule both worlds, and searches for the "key" which holds tremendous power. A young boy from Elde by the name of Sōta meets a mysterious girl from Fandavale, Akazukin, and her talking wolf companion, Val. Sōta learns that he is the key Cendrillon is searching for. Now it is up to Akazukin, Val, and the other Fairy Musketeers to protect Sōta from Cendrillon and her Nightmarelians who wish to obtain the power he mysteriously possesses.

High school science-whiz Makoto Mizuhara is working on his newest project in preparation for the school festival, alongside his best friend Nanami Jinnai. Nanami's brother and Makoto's lifelong rival, the unscrupulous student council president Katsuhiko Jinnai, is under scrutiny for mishandling the school festival planning and is convinced that Makoto is plotting to steal his position. One night, as Makoto and Nanami are taking a break with their teacher Masamichi Fujisawa, Jinnai sneaks into the science lab and sabotages Makoto's device, which suddenly opens a portal that flings all four of them into another world! Upon arrival, Makoto is immediately attacked by a horde of giant bug monsters. While running from them, he comes across Fujisawa and a girl named Rune Venus. After Fujisawa fights off the monsters, a group of dignitaries arrives, looking for Rune, their princess. They inform Makoto and Fujisawa that they are in a world called El-Hazard and take them back to the palace of Roshtaria, their kingdom. Though her advisors are suspicious of the newcomers, Rune decrees that they are to be treated as guests and quickly befriends Makoto. Unaware that Nanami and Jinnai are in this world as well, Makoto gets to work trying to figure out a way back to Earth.