People are disappearing, and an abandoned warehouse seems to be involved. Your character investigates, only to discover a secret government facility. What are they doing here that is causing the disappearances?
Whether you're writing a mystery novel, a short story, a play, or any other type of creative writing, photo writing prompts are a great way to jump-start your creativity. Once you get started, it's just a matter of increasing the suspense until your character solves the mystery.