On the day Touma Kamijou and Index see Academy City's space elevator, Endymion in the distance, they meet a Level 0 girl with an amazing singing voice, Arisa Meigo. As the three enjoy their time together after school, magic-user Stiyl Magnus suddenly attacks them. His target: Arisa. Why would a girl from the science side be targeted by someone from the magic side, Touma wonders. In the chaos of Stiyl's attack, he tells Touma, Index and Arisa that she might cause a war between the magic side and the science side.

High schooler Hibiki is transported to a monster-filled fantasy world, where he possesses only non-combat skills. However, through key encounters, he discovers hidden powers and embarks on an epic adventure.

Maki Maehara, the class outcast, finally makes his first friend: Umi Asanagi, the second-prettiest girl in class and the center of everyone’s attention. He’s convinced she’s out of his league, but as their unlikely friendship grows, Maki starts to wonder…could there be more than just friendship between them?