Frank Bigelow, told he's been poisoned and has only a few days to live, tries to find out who killed him and why.
 
FUN FACT:  The scene in which Bigelow runs in panic through the streets after learning he has been poisoned was what is considered a 'stolen shot' where the pedestrians along the sidewalk had no idea a movie was being made and no warning that Edmond O'Brien would be plowing through them.