This is a worldwide experiment, with forty-four children with special blood types selected from all over the world as experimental subjects. The purpose of the experiment is unknown, but it is announced that it is to study whether the living habits of people with this special blood type are different from normal people.
However, no one except the children's parents would care about such an experiment. However, even the children's parents do not know the true purpose of this experiment. There is a deeper meaning behind the experiment.
The experiment went on like this, with its purpose unknown.
What kind of bond will form between classmates who have been together day and night for more than ten years? When a disaster strikes, what kind of reaction will there be among the classmates?