Jinks has just finished watching a television show called "Mark of the Mouse" and he thinks it's just baloney. He hears the mailman come and Dixie sounds excited. He goes to the window and sees that Dixie has gotten a Mark of the Mouse costume complete with a rubber sword. Jinks decides to play a prank on the mice.
Dixie approaches Jinks in his costume and threatens him. Jinks pretends to be scared and runs. Jinks then gets a real sword off the wall and when Dixie comes he starts chasing and poking him with the real sword. He chases the mice back into their hole and laughs that they would believe that the Mark of the Mouse was real.
The real Mark of the Mouse shows up in the window and challenges Jinks. The Mark of the Mouse defeats Jinks and makes him promise not to chase mice anymore. When the Mark of the Mouse leaves, Jinks yells that he doesn't believe that he was real because he doesn't see where he left his mark but what Jinks can't see is the big "M" that is on his rear end.