The main character Code Realize Sousei no Himegimi is a girl named Cardia. A mad scientist injected her with a poisonous serum when she was a child. Because of this, she developed a strange and monstrous ability. Any person she touched began to rot alive. From an early age, she lives in isolation; society cannot accept her gift. Behind her back, she is known as a witch and a fiend of hell. She is forced to behave carefully and cautiously. One day, she meets a strange gentleman who calls himself a noble robber.

The plot of Code Realize Sousei no Himegimi takes place in aristocratic London. The young lady met Arsen Lumpen and the inventor Impi. He is famous for his ideas, and will definitely end up on the Moon. From this moment on, amazing and unforgettable adventures begin. The main task of the trio is to find the elusive criminal who has enveloped the entire city in a criminal network. In the process of passing, you will have to encounter secondary characters. Some will be positively disposed towards the company of young people. Others weave intrigues, are capable of betraying at any moment. Also here you will have to participate in chases, shootouts, fights and visit other regions of the country. The action is made in the form of an illustrated novel, and is based on dialogues between the participants. The development of events depends on the decision made, the chosen phrase. In the end, you should find the answer to the question of who Cardia really is.