Isazuki Village is a village with a deep, strong faith in the Inugami folklore. As the opinions of redevelopment of the village are divided among the villagers, they are greeted with the strange deaths of the people from a construction company who had come to investigate the village. Tachibana Tsukiko, who lives in this village, and her three childhood friends are getting ready to participate in the annual festival that seeks to drive away the Inugami spirit. However, they end up getting caught up in a certain incident…?! This dark, young-adult tale of childhood friends begins here…

From MangaHelpers:
One day, Matsui Sakura receives an invitation to a "Revenge Game," and decides to attend. At the location indicated, she ends up locked in a dorm-like building with four of her classmates. It appears that the Revenge Game is being run by a wealthy classmate, Saionji, who was bullied so badly by some of the students that it ruined his life. Now he is taking his revenge, in a brutal game that allows him to have one of his former tormentors killed each morning.
However, Sakura--a lonely, quiet, orphan girl--does not understand why she is there, unless it was due to her inaction in stopping the bullying of others. She's also the only one who received an invitation, while the others were abducted or tricked into attending. What is the final purpose of this game?