The Rat Pack is a biopic that follows Frank Sinatra and his group of friends, known as the Rat Pack, during the years 1960-61.
During this time, America is undergoing significant change. Sinatra decides to throw his support behind John F. Kennedy for President and works to rally his friends to do the same.
However, Sinatra is dismayed when Joe Kennedy pressures him to use his alleged mob connections to ensure his son's victory in both the nomination and the election.
Meanwhile, Sinatra's friend Sammy Davis Jr. falls in love with May Britt, but Sinatra is once again pressured not to support their wedding, fearing it may alienate southern voters.
As Sinatra is tasked with organizing the inaugural ball, he is forced to exclude Sammy for the same reason. The situation worsens when President Kennedy chooses to stay with Bing Crosby, a Republican, instead of with Sinatra during his visit to Los Angeles.