It's January 2019, and the Japanese calendar will soon be turned over into the Reiwa era. Gump is a aging cartoonist who's nearing 40, and just had additional printings of the volume releases of his manga for the first time in his life. The future was looking bright for him, until things took a sudden 360 degree turn for the worse when his doctor informed him that he has colon cancer. It didn't seem real to him at first, but as the days carried on, he watched his wife beside him be overcome with grief. Gump begins to take the feelings that are gradually bubbling up inside of him and draw them to leave behind as a record of the "days of his life". Thus, this is the account of an almost-40 cartoonist's tedius fight against cancer.