Lonesome Jim Barkley in Boomerang Bounty has successfully concealed his past involvement in a robbery, but banker Tade Wardow knows Lonesomes secret, and uses that knowledge to coerce Lonesome to commit a new crime. The only way out for Lonesome is superior cunning. Retirement Day is what awaits old Joe Mills, long-time stage driver, after one final run in stormy weather with only his grit and determination to see him through.