Yukio Kunikida and Yuma Yamagishi are high school students, and they are dating each other. On an ordinary day, Yuma Yamagishi tells Yukio Kunikida, "I'm going to die in a week." She knows that her illness has progressed and has accepted the fact that her days are numbered. She wants to live the rest of her days being true to herself. Yukio Kunikida finds it difficult to accept that Yuma Yamagishi has just a short time left to live, but he busies himself fulfilling her wishes. (Source; AsianWiki) Adapted from the novel "Happiness" (ハピネス) by Takemoto Novala (嶽本 野ばら).