在黑暗的角落里，孤独的回声映照出内心深处的伤痕与渴望。调教师的惩罚手段

　　Several young couples travel to a private island for a mysterious training retreat that promises to strengthen their relationship. However, during the Retreat, the heroes encounter an ancient demon - a Succubus. This monster feeds on the life energy of people, taking on someone else's appearance and provoking victims to show the worst qualities and do terrible things.