[1] Just out of jail, Gruesome (Boris Karloff) goes to the Hangman's Knot saloon, where his old crime crony, Melody (Tony Barrett), is now playing piano.

Gruesome takes him to a plastics manufacturer, where X-Ray (Skelton Knaggs) and a mysterious mastermind are in possession of a secret formula and hatching a sinister plot.

Ignoring a warning not to touch anything, Gruesome sniffs the gas from a mysterious test tube; he escapes the toxic fumes but collapses upon returning to the Hangman's Knot and is taken to the city morgue, where his body stiffens dramatically.

Dick Tracy (Ralph Byrd) is at headquarters speaking with college professor Dr. A. Tomic (Milton Parsons), a scientist who suspects someone has been following him.

Pat describes him to Tracy as looking a lot like the actor Boris Karloff (a gag cribbed from Arsenic and Old Lace).