Casey takes a job as a factory file clerk in order to investigate a suspicious fire. Evidence points to a secretary with a history of mental illness, but Casey suspects that an arson ring may be responsible.
When a roll of blank parimutuel tickets are stolen from a race track, Casey attempts to convince the gang responsible that she's a cop on the take who can help them pass the counterfeit ducats through crooks she's blackmailing.
Casey moves into a seedy rooming house to try to befriend a woman whose boyfriend is a suspect in a robbery and murder, but she senses that something is not quite right.
Newly arrived in New York, a young Puerto Rican man is arrested for robbery and assault. He claims to have been with two women at the time of the theft, but one won't identify him and the other can't be found.