20 year old undergraduate Kazuya has just been dumped and unable to get over his ex-girlfriend Mami, he decides to use some of the tuition money his parents gave him to spend a day with a rented girlfriend of his choice, Chizuru Mizuhara "Ichinose". However, during their "date" he receives a call that his dear grandmother had...

Maru has been tasked to find a place known as "Heaven" and is escorted by his "big sis" Kiruko Takehaya in a world where the Great Disaster occurred a number of years ago. Kiruko herself was trying to trace old acquaintances too. As they discover new clues and meet other survivors, they barely find any edible food in abandoned...