One day, a hikikomori with the ability to see ghosts receives a text "Help me" from an anonymous source. Feelings of heroism coax him to venture out to the outside world which he finds has been badly damaged, with broken houses and bits of debris everywhere. He searches for survivors but all he finds are corpses and ghosts till he gets to his sister's body. He converses with her ghost and she tags along in his attempt to find more survivors. Eventually they do find someone who is alive, but they may not be as human as they seem...