Judge Crowdy Lobbett has found evidence pointing to the identity of the criminal mastermind behind the deadly Simister gang. After four attempts on his life, he ends up seeking the help of the enigmatic and unorthodox amateur sleuth, Albert Campion. After Campion bundles Lobbett off to a country house in Mystery Mile, deep in the Suffolk countryside, all manner of adventures ensue. It's a race against time for Campion to get the judge to safety and decipher the clue to their mysterious enemy's name.