A female doctor from a rural clinic was brutally murdered in a secluded playground in full view of everyone.The swing was stained red by blood, and fear and confusion spread among the onlookers.This horrifying murder led a team of detectives to an increasingly dark, foggy mystery.They crossed the European continent and tracked clues that were looming - and all of this originated from notes quietly sent by a mysterious "ghost detective".Those sloppy but extremely accurate information seemed to come from another world, leading them step by step to the abyss of truth.