|Spoiler Warning: Plot details, ending details, or both are in the text which follows.|
The Rose Mansion is the fiftieth episode of the anime.
Inspector Lunge visits Jan Suk in the hospital and talks with him about the murders he has been accused of and the attack he suffered, then advises him to start doubting of the person he would doubt the least, hinting that Johan acting as Anna Liebert might be responsible for all this.
Lunge gets an interview with Karel Ranke. Lunge tells Ranke that he is in Prague searching for the existence of true terror. Lunge points that Ranke may have created an incarnation of the devil himself. They talk about Franz Bonaparta and The Red Rose Mansion. Ranke tells that, one day, all the political prisoners and researches held at the mansion vanished. Lunge asks Ranke for permission to tear down one of the walls of the mansion that might be hiding something. Ranke accepts but warns Lunge.
Tenma visits Mr. Sovák, a former publisher from Bonaparta when he went by the pen name Klaus Poppe. Sovák tells that Bonaparta was a psychologist and a medical doctor. Sovák remembers that the las time he saw Bonaparta was in 1981 or 1982, when Bonaparta came with a new story: a story about a monster falling in love. Once Tenma leaves, Sovák calls the police after seeing Tenma's picture in the newspaper.
In the mansion, Lunge breaks the wall and finds a door behind it. Lunge notices that the room reeks of antiseptics, suspecting that many people had died in the room. There is a portrait of a blonde woman hanging from the wall, Lunge infers that it is the mother of the twins from the sketchbook.
Grimmer tells Tenma that he plans to send a letter to the police blaming himself for Petrov's and Zeman's murders and then they part ways. Soon after, the police arrives and arrests Tenma.
- Heinrich Lunge: "If you don't want to be betrayed anymore, then start doubting the person you want to doubt the least."