In most ordinary high schools, many stories and rumors float around—some scandalous, some happy and some...more macabre. One such example is of monsters lurking in an abandoned mansion outside of town. Such tales, however, prove too tempting to resist for Hiroshi and his friends Mika, Takeshi, and Takurou. They decide to brave the rumored dangers in order to investigate the manor and complete a test of courage. Each of them approaches the mansion with an overwhelming sense of dread. And when they enter, they come upon a blue monster named Ao Oni who attacks them. As Hiroshi and his friends try to solve the various puzzles in the mansion and escape their new blue nemesis, they find themselves meeting several horrible endings as they fail miserably.

I, Maehara Maki, struggled to connect with anyone during my high school years, finding it hard to make friends. Then, a turning point arrived. A girl named Asanagi entered my life. Despite being clandestinely referred to as the second cutest girl in class by the boys, she chose to spend her Fridays with me instead of her best friend Amami, who held the cutest girl in class title. In the comfort of my home, we delved into the realm of games, watched movies, immersed ourselves in manga, indulged in junk food—pizza, hamburgers—and guzzled cola, carefree and content. To the outside world, we might have seemed a bit messy, but to both Asanagi and me, it was a cherished, hidden time together. (Source: MAL News)

After losing their magical abilities, the girls once again become witches. However, now they have to go through tests from the Witches of the Witch World. They also meet a new member from New York, Momoko.

Bonus animation featuring Index-tan included with the BD special edition of the Toaru Majutsu no Index: Endymion no Kiseki movie.