One day protagonist meets with four sisters, who due to certain events starts living in his house. But he has to go to Europe to follow a story, and they decide to go together with him. They make reservations in an old castle which had reports of a princess' ghost, a legendary wolf, a lake monster and a crashed UFO surrounding it. And this is not even the beginning of the events to unfold around the sisters ... A crossover between multiple âge works, various characters from other companies games such as Hateao, PHANTOM and Pure Mail make appearance.