Two detectives help an escaped convict who was framed for the murder of his manager. In order to elude the police, the convict takes a serum that makes him invisible.
This is probably the best of the several horror-oriented followups that Abbott and Costello made in the wake of ABBOTT AND COSTELLO MEET FRANKENSTEIN. Like that one, this has a definite storyline, even if the concept of an invisible man trying to prove his innocence was used before. Nonetheless, a storyline gives the viewer something to follow when the gags fall flat; it also pushes the story in some different directions so we don't have a succession of "Lou is scared" gags; having Lou pose as a boxer in an attempt to catch the real criminal (Sheldon Leonard) gives them a pretty good framework for some of the later gags, particularly the extended fight sequence in the last third of the movie. Arthur Franz plays the convict/boxer, and William Frawley is on hand as the chief of police. There are several other nice character parts throughout the movie.