"The Blood Pledge" is the fifth instalment of the popular "Whispering Corridors" horror franchise. It follows four good friends in a Catholic girls' high school - Unjoo, Soy, Eugene and Eun-young, who swear their friendship with blood late one night at chapel within their school compound. They promise each other that their bond will last through death, so much that they are even willing to die together. Strange rumours start to spread at the girls' school after Unjoo committed suicide one night. Unjoo's younger sister Jung-un who attends the same school gets suspicious about Unjoo's death. The remaining friends are then chased by death as their promise weighs heavily over them.