Gin no Valkyries

Ruka has long had a recurring dream of a silver knight calling her name. Due to her shyness, she has never had a boyfriend in her 17 years. A rumor spreads about a stone that allows the dreamer to experience pleasant dreams. After a strange occurrence, Ruka tries the stone and enters a dream. However, the dream is not what she anticipated. She wakes up not in her bed or her world, but in a new world ruled by Valkyries.