The story of a super-secret spy organization that recruits an unrefined but promising street kid into the agency's ultra-competitive training program just as a global threat emerges from a twisted tech genius.

4月。下雨的早晨。开始凋零的樱花被雨滴打落，漂浮在积水之上。学生们撑着五颜六色的雨伞，穿过高中的校门。
“早啊，莲”。鞋柜前，裤袜湿透的莲被由亚搭话。略显忧郁的莲回过头去，看到全身湿透的帆美蹦蹦跳跳地走来，热闹地说着话。3个女学生没啥营养的对话，向教室宣告了新学期的来临。
少女们无可替代的宝贵时间向前飞逝，季节渐渐转变……