Watanabe Gisuke, 77 years old. Having resigned from his position as a university professor for 10 years—predeceased by his wife, he lives in a traditional Japanese house passed down from his grandfather's generation. He cooks for himself, enjoys his evening drinks, has drifted apart from many friends, but shares drinks with a few close friends, sometimes inviting former students for dinner. While calculating how many more years his savings will last, in other words, how many more years he will live, he peacefully goes about his daily life, preparing for the days ahead. He has also written his will. There is nothing left undone. However, one day, an unsettling message "The enemy is coming" appears on his computer screen.