Dr. Hibiki, a neurosurgeon working on the controversial Ghost Brain project, returns home after five years to find three teenage girls he doesn't recognize living with his wife, Ako. Accused of infidelity and faced with a family in turmoil, Hibiki struggles to understand his situation while dealing with strange occurrences, such as vivid dreams.
As tensions rise and relationships strain, Hibiki attempts to mend familial bonds by planning a Halloween celebration. However, the lines between reality, memory, and the supernatural begin to blur, forcing players to piece together the truth behind Hibiki's absence, his research, and the mysterious family dynamics.