The mice of Cheeseville are able to protect themselves from the cats with an alarm that warns them of the approach of feline foes. Mighty Mouse is so grateful for the invention of the alarm that he takes a much-needed vacation to Florida. But the cats plot to capture the mice by faking a news broadcast to Mighty Mouse that the Mouseville dam has burst and a gigantic flood is headed for the town. Flying back to Mouseville at top speed, Mighty Mouse warns the populace of the approaching doom and sends the mice to a cave where the cats trap them. When he becomes aware of the deception, Mighty Mouse flies to the cats' mountain hideout, where he not only saves the citizens of Mouseville, he clobbers the cats and traps them inside their own mountaintop hideout.