After his retirement from the intelligence services where he worked on cryptography during the cold war, George became editor and compiler of the crosswords of the Times and Sunday Times newspapers. For more than thirty years he cracked the brains of readers who struggled to complete his cryptic crosswords. When an old colleague asks him to place a code within one of the Sunday Times cryptic puzzles George is unaware that this is the catalyst for a number of gruesome deaths.
A father of one of the victims, known for his horrific torture methods during the breakup of Yugoslavia, discovers the puzzle maker has something to do with his son's death, and goes on the hunt. Georges' quiet world of puzzles changes into a nightmare of being hunted and a fight for his life. While on the run he tries to decipher that last fatal cryptic message he got from his friend, who has now disappeared, and solve a puzzle that will hopefully save his own life.