Sadako at the End of the World (manga)

In a world torn apart by an apocalypse, two lonely little girls chance upon a strange video. To their surprise and joy, a girl with long black hair named Sadako climbs out of the TV...But little do they know that Sadako is a vengeful ghost who will kill them in a week! In order to help their new friend, these two sweet, innocent girls begin a journey to the end of the world to look for more victims friends. Can their bond with Sadako help her find peace and finally break the curse? Or will this tale have a tragic ending...?