In Academy City, where esper abilities have been recognized as a general science. Behind the peace, there is a dark side organization that undertakes missions that cannot be made public.

"Item" is an elite unit consisting of four girls. Takitsubo Rikou is able to read and track the weak power emitted by those with abilities. Frenda Seivelun, who excels in combat using explosives and traps. Kinuhata Saiai, who can manipulate nitrogen at will and plays a defensive role. And one of the 7 espers that Academy City is proud of: Mugino Shizuri. They live freely in the darkness of the Academy City, and quietly set their sights on their target...!

This is a story of encounter, friendship, and darkness that eventually leads to a 'terrible incident'!