Indicia title is "FRANCIS, THE FAMOUS TALKING MULE, No. 1090." Code number is FRANCIS O.S. #1090-604. Copyright 1960 by David Stern. Last of seventeen Francis the Talking Mule Four Colors. Based on the "Francis the Talking Mule" movie series.
Pete and Francis are part of a covered wagon mule train that is to travel across the country. Among the travelers is a gang of bank robbers, who plan on pulling jobs in each city the mule train stops at. After they rob the bank in the first town the train stops in, Francis finds the stolen money and ends the scheme.
Two government scientists hire Francis to take part in some top-secret space flight tests. Pete is also part of the tests, but neither knows why they are being tested. Francis then overhears the scientists talk about sending him aboard a rocket into orbit where he'll be able to report conditions because of his ability to talk.
An sheik is the ruler of the only Arab land that doesn't have oil. He is told by his soothsayer that his problems will be solved if he can find a "man who speaks like a jackass". One of the sheik's agents in America encounters Francis, and thinking the search is for a "jackass that speaks like a man", takes Francis and Peter back to his country. Francis is given an ultimatum--find oil in three days or Peter will die. Francis doesn't find oil, but Peter does, as he's digging his own grave!
Peter's last name is spelled "Sterling" in this story. In all the movie references it is spelled "Stirling". Last panel is Dell's "A Pledge to Parents".