HAPPILESS

A mysterious organization conducting soul-swapping experiments runs through the entire story, presented in an episodic format that explores how the characters face their respective challenges after participating in the experiments.
The series spans three seasons, each featuring a different pair of participants in the soul-swapping experiments. As each season progresses, the true purpose of the experimental organization is gradually revealed.
Due to the success of the three experiments, the doctor also faces his own dilemma; should he help the investors undergo a soul swap to extend their lives? The soul containers that the investors wish to use are the doctor′s assistants, who are his colleagues and have a familial bond with him.
The doctor recalls how he initially joined the experimental organization. At that time, he was an abandoned child, smuggled into the laboratory by a human trafficking group. The teacher at the laboratory protected him and taught him all his medical knowledge. He inherited the teacher′s will and stayed with the organization.
In the final part of the story, under pressure from the shareholders, the doctor must begin the soul transfer process. Inside the laboratory are three incubation chambers, each containing the body of his assistants. However, the doctor has secretly planned a rebellion. He has already mapped out an escape route, and after assisting his assistants in escaping, he remains in the laboratory and sets it on fire, burning all the research secrets.