Based on the mysterious legend of Idilia Dubb. Germany, 19th century, Middle Rhein Valley. The dreamy Idilia (Lea van Acken) awakes injured in the midst of a gloomy castle ruin and can't remember anything that happened before. When she discovers in horror that there is no escaping the towering castle walls, she begins a grueling fight for survival. Only her nebulous diary can help her decipher the past, which exposes a secret romance with Abyssinian actor Caven (Eric Kabongo), a performer in a human zoo exhibition run by her fiancee Franz Hagerberg (André M. Hennicke). Idilia's written record, however, blurs the lines between reality and fiction.