Themes in the 'big brother dark silver story' could also include loyalty and betrayal. Suppose there are other characters in the story. They might either be loyal to Big Brother or betray him because of the dark silver. Or it could have a theme of survival, where Big Brother has to survive in a world where the dark silver is both a source of danger and opportunity.
I'm not sure specifically which 'big brother dark silver story' you're referring to. It could be a unique story created by someone. Maybe it's about a character named Big Brother who has something to do with dark silver? Without more context, it's hard to say more.
Another theme could be growth and learning. The big brother could be teaching Alice new things, helping her grow as a person. So, the theme of personal development might be in the story. Also, if they face any difficulties together, the theme of perseverance could also be present.
Isolation could be a theme. In the dark, one can feel very alone. If it's a story about a person in a dark place, they might be cut off from others and have to deal with their situation by themselves. Also, survival can be a theme. If the 'in the dark' situation is dangerous, like in a dark cave full of hazards, the characters would be focused on surviving.
One possible theme could be family bonds. The story might show how the family members are connected to each other through their shared experiences near the Silver River.
One possible theme could be discovery. If the silver star is something rare or hidden, the characters might be on a journey of discovery.
One possible theme could be exploration, as it might involve exploring a lunar - like environment. Another could be the beauty of silver, perhaps representing something precious.
Isolation could be a theme. A dark tale might be set in a desolate place or the characters might be isolated in some way, which adds to the overall sense of gloom. Also, the theme of loss can be present. This could be the loss of a loved one, of innocence, or of hope, all of which contribute to the darkness of the story. For example, in a story where a character has lost their family in a tragic event, it sets a very dark mood.
One possible theme could be fear. The darkness of the room can symbolize the unknown, which often induces fear in people.
Another theme might be isolation. At night, especially if it's very dark, a person can feel alone and cut off from the rest of the world. This sense of isolation can be a strong theme in the story.
One possible theme could be fear. The very idea of a dark house often evokes a sense of unease and terror. Another theme might be mystery. There could be secrets hidden within the walls of the house that the characters are trying to uncover. For example, the mystery of what happened to the previous owners or what lurks in the attic.