In the technologically advanced Academy City, a marvel is poised to unfold: the inauguration of the globe"s inaugural space elevator, "Endymion." At the same time, a particular high‑schooler, Touma Kamijou, and his ally Index navigate their everyday routine when they meet and become friends with Arisa Meigo, an exuberant and driven vocalist. As odd incidents erupt across the metropolis, they uncover a complex scheme tied to Arisa and Endymion. The plot thickens further when the Stiyl Magnus arrives, indicating that a supernatural realm is entwined as well for the grand scheme.