"Sister Mashiro, tell me you love me."

Mashiro lives as a "powerless" person without any special powers in the prestigious Amamiya family, and is treated harshly by her mother, while her father treats her like air. Her talented stepbrother Hiiragi is her only support. One day, Mashiro begins to see mysterious images in fragments. Eventually, she realizes that these are images of the future, and that her special power is "future foresight," but it was just delayed in manifestation. She is shaken by the frequent images of herself being embraced by her stepbrother, she even sees a future in which she is killed by him--!?