Law professor Natalie Greco has an ordered life. Then everything changes. Nat accompanies her colleague to a prison where he’s a guest lecturer. However, the trip turns grim when they arrive at the prison; they’re smack in the middle of a riot. In front of a horrified Nat, a prison guard is fatally injured. Nat rushes to help him, only to hear his last words: “Tell my wife. It’s under the floor.”
With her career in the balance and her life on the line, Nat sets out to save herself by deciphering the puzzle behind the dead guard’s last words.