Yesterday the doorman at Big Digger's apartment house made the singular mistake of attempting to blackmail him, and so Big Digger tricked him into a meeting on the retaining wall overlooking the underpass through the park. Once there, Big Digger beat the doorman groggy with the barrel of his gun, and then hurled him into the underpass in front of a racing car. But, before the doorman died, he tried to leave Tracy a message...