Keiichi Maebara has just moved to the very small town of Hinamizawa. He's making friends and enjoying life, until he learns of a murder that took place in a small village. His friends won't tell him the details, and at the town's yearly festival he finds out that there has been a death on that night every year for four years, and it's attributed to the Curse of Oyashiro-sama - a punishment for those who supported the dam project that would have put the town underwater. Another death occurs and the police ask for Keiichi's help in their investigation. Over time his friends become more suspicious as he gets closer to the truth, and as his paranoia mounts he discovers his friends are closer to the curse than he thinks!