Seeking shelter from a fierce storm, a group of field mice enter the infamous Dr. Jekyll's house. Upon seeing them enter, the doctor's cat lures the field mice into the creepy house with cheese. The cat chases them, ultimately crashing into the laboratory, where he mixes up some of the potion. He ultimately transforms into a demonic creature, then rounds up the field mice and poisons them. Mighty Mouse comes to their rescue; in the fight, the doctor's laboratory catches fire. The field mice escape, but the house rockets into the sky and explodes into fireworks.
