Anna and Joe are newly married, playful and deeply in love. Joe is scraping by as cab driver in New York City during a period of corruption, mob control and violence between cab companies.

Allen Meighan, an intern, assures himself residency at 'General Hospital', when he saves the life of a man trapped in an explosion. Allen is in love with student nurse, Claire Donahue, and she with him, but, she is married to Tom a physically abusive husband.

Wrongfully convicted of a robbery and murder, Paul Lavond breaks out of prison with a genius scientist who has devised a way to shrink humans. When the scientist dies during the escape, Lavond heads for his lab, using the shrinking technology to get even with those who framed him and vindicate himself in both the public eye and the eyes of his daughter, Lorraine. When an accident leaves a crazed assistant dead, however, Lavond must again make an escape.

A fur trapper catches another trapper trying to steal his furs. He stops the thief, but later on the furs are stolen anyway. Rin Tin Tin Jr. tracks down the thief to try to get the furs back.