Watch Serpico for Free: How to Stream the Movie Online at 123Movies. . Frank Serpico is an idealistic New York City cop who refuses to take bribes, unlike the rest of the force. Frank's actions get him shunned by the other officers, and often placed in dangerous situations by his partners. When his superiors ignore his accusations of corruption, Frank decides to go public with the allegations. Although this causes the Knapp Commission to investigate his claims, Frank has also placed a target on himself.