Mighty Mouse; The Claw; proto-version of Professor Edam; Joe (mouse lab assistant), various mouse citizens of Terrytown; cat fighter pilots
Synopsis
Mighty Mouse agrees to be the test pilot for an experimental saucer-like spacecraft intended to take the Terrytown mice off-Earth, and away from the cats forever. The Claw gets wind of this and leads a cat fighter-squadron to obliterate the spacecraft.
A tall (for a mouse), lanky, bearded mouse character, referred to only as "The Professor", appears in this story. This would seem to be the prototype for the later, recurring mouse scientist Professor Edam.