The protagonist Sachiko Tachibana (Nozomi Sasaki)) vows to fight against the demon-like ruthless monster Hanai Rina (Shibuya Nagisa)act) revenge.In high school, Sachiko was teased as the daughter of a murderer, and Rina became her only friend.However, behind Rina's angelic and gentle smile, there is a face of a murderous demon who easily kills people.Rina charged Sachiko and her father with murder, and also took the life of Sachiko's father.

14 years later, Sachiko, whose appearance has completely changed from her past, once again confronts Rina, who has become a new mother.“Let her taste the taste of living hell”, Sachiko enters Rina's family as a nanny.Can ordinary people who devote their lives to revenge drive monsters to destruction?A heroic revenge drama with repeated setbacks and entanglements begins. 

The nanny Sachiko Tachibana (Nozomi Sasaki) comes to the home of Rina Hanai (Nagisa Shibuya), a pianist and internet celebrity.Sachiko is interviewing Reina because Reina wants to find a nanny for her newborn daughter Kotoko (Shibata Honno).

They had many topics in common, and the conversation was harmonious, and Sachiko felt hopeful.However, due to Sachiko's inexperience, Reina plans to reject her application for employment.Rina felt a little uneasy about Sachiko who was too eager, but Sachiko noticed that there was eczema at the corner of Xiaoqin's mouth...

Sachiko greets Reina and says it's our first time meeting her, but in fact Sachiko's true identity is Bando Yukiwako (Watari Mai) who was in the same school as Reina 14 years ago.At that time, Xinghezi's father was suspected of murder, and she was laughed at every day as a murderer's daughter.But Sachiwako firmly believes that her father is innocent, and her only supporter is her school girl Rina.

Sachiwako completely trusted Reina, and one day, Reina called Sachiwako to the music room.However, when she gets there, she finds Rina holding scissors and covered in blood...!?