Grandpap has an uncanny way of guessing the contents of the unlabeled canned goods in the store. It has nearly ruined the success of the grab bag sale, and been the cause of some bad blood between grandpap, and Lum and Abner. Lum has threatened an injuction against grandpap to keep him out of the store, but it was just an empty threat. Now that grandpap has made himself unwelcome, he hasn’t been back, but now other people have had a run of luck in guessing what’s in the cans.
Mousey Gray enters to make a guess, and walk away with a couple free cans. Does he know the secret of the guessing game? Is the code numbers printed on the bottom of the can the way to tell what’s inside? Is it just a fluke of the law of averages? A law that gets Abner a little confused.
Cedric enters, guesses right, but will he expose the secret? After more confusing talk about laws of nature, Lum and Abner discover that grandpap is behind the run of luck. He’s hiding outside, and giving tips to customers who enter.