Wang Luoluo is the monitor of the fourth class of Fucheng Shuhua Primary School. In the corridor of the unit building where she lives, there has been a mysterious green iron door since she was a child. Ever since he could remember, Wang Luoluo had never seen this iron gate open. Until one day, when Wang Luoluo came home, he saw that the iron door seemed to have been opened a crack. The curious Wang Luoluo couldn't help opening the door, walked in, and discovered a secret that had been hidden for many years.
Wang Luoluo, who knew the secret, couldn't help but tell her three good friends in the same class - Pan Xiaotuan, Chen Li, and Li Yuanyuan - what she saw and heard.
The four little girls decided to protect this secret together, but they experienced a thrilling adventure story together.
Mission: Girls save the world