There are three parallel worlds. The heroine travels to the second parallel time and space. That time and space is exactly the same as the heroine's original time and space. However, the heroine cannot find her shadow in the second parallel time and space. At the same time, no one in the second parallel time and space recognizes the heroine. Why is it that only the hero knows that the heroine comes from somewhere else. And why the male protagonist doesn't know about the first parallel time and space. And why does the male protagonist love the female protagonist so much? But later on the male protagonist no longer loves the female protagonist. Why?