The Earth receives an influx of X refugees, who were deported from their home planet due to a dispute. Countries on Earth agonize over how to deal with the influx of these interplanetary immigrants. The American and Japanese governments announce that they will accept X refugees. The X refugees transform their appearance into human beings and live among ordinary humans. Residents in the host countries are unable to distinguish X refugees by appearance and they have no idea if any of them live among them. People become anxious, confused, and afraid of the X refugees and they try to find the refugees who may live among them. Kentaro Sasa is a weekly magazine journalist. For a story, he hides his identity as a journalist and approaches Ryoko Kashiwagi, who is suspected of being an X refugee. He gets close to her and becomes to have feelings for her, but he's not certain if she is human.