Medic horror: About the story

A junior high school student went to an abandoned hospital with his brother and his friends on an expedition, but didn’t know that they had fallen into the trap of a ghost that had been sealed for thousands of years and could only be active in the hospital. Tong's expedition turned into an adventure that frightened and wandered between life and death. The junior high school student decided to explore and discover the past history of this hospital and its secrets, but in exchange for his special identity and adventures related to his identity. Can they escape and destroy the Eidolon? And what is the true identity of junior high school students? And who is that phantom? What is the inextricable relationship with junior high school students?