AI: The Somnium Files is a mystery adventure and visual novel set in a near-future Tokyo. Players take on the role of Kaname Date, a detective with a secret police unit who investigates crimes using an experimental technology that lets him dive into the dreams of witnesses and suspects. Aided by an artificial intelligence named Aiba housed in his prosthetic eye, Date is drawn into a chilling serial-killer case that begins with a gruesome murder. As he alternates between examining crime scenes and exploring surreal dream worlds for hidden clues, the branching investigation gradually pulls him toward buried secrets connected to his own lost past.