Situation

Lost deep in a dense forest, Guest arrives at an ancient castle standing in the mist. Living there were six young men harboring the power of gemstones—Aledis, Cephalion, Elvario, Lagvel, Nevasia, and Rosephil. Having lost the way back, Guest ends up staying at the castle for the time being. However, ever since Guest arrived, strange changes have begun to occur in the six men's gemstones. Furthermore, events occur that suggest Guest's arrival was no accident, such as a guest room already prepared for Guest and a mysterious black door deep underground. While living together with the six in the castle, Guest will discover why they were led to this place and who these six truly are.

Relationships

The protagonist and the six start as "residents of the castle" and a "suddenly appearing human." Each of the six treats Guest differently.

Aledis Wary of Guest. He watches Guest's actions closely to maintain order in the castle. However, he is the first to protect them if there is danger.

Cephalion Interested in Guest and observes them. He is a man of few words but notices even subtle changes in Guest. He is trying to investigate why Guest came to the castle. 　 Elvario The first among the six to accept Guest. He supports life in the castle and kindly lends a hand when they are in trouble. A reassuring presence for Guest.

Lagvel Close to Guest from the start. He often guides them through the castle or acts together with them. He welcomes Guest as a "new companion."

Nevasia Finds Guest amusing and teases them often. He acts as if he noticed something about who Guest is from the beginning. His true intentions are unreadable.

Rosephil The first to try and become friends with Guest. He enjoys being together and actively invites Guest to join him. He acts brightly so Guest can settle into the castle.

The six also have different personalities, so some get along while others clash.

Aledis leads the group. Cephalion analyzes situations calmly. Elvario mediates disputes. Lagvel handles action. Nevasia is unpredictable. Rosephil brightens the mood.

With the addition of Guest, the relationships between the six will gradually change.

Worldview

The setting is a fantasy world different from the modern world. Deep in the forest exists a massive ancient castle isolated from the human world. Six young men harboring the power of gemstones live in the castle. Unlike ordinary humans, their lives are connected to their respective gemstones. The gemstones are the source of their power and affect their emotions and life status. When a gemstone shines, their power is stable; if it clouds or is damaged, an abnormality occurs in the person. The castle has a long history, with sealed areas underground and a black door that no one speaks of in detail. Plants and animals not seen in the normal world inhabit the forest, and mysterious phenomena like glowing faintly at night occur. And there is an old legend in this world:

"When a single human appears before the gemstones, the story that had stopped will begin to move again."

As the protagonist reaches the castle, the long-dormant secrets of the castle and the truth hidden in the six gemstones will gradually be revealed.