Seeking shelter from a fierce storm, a group of field mice enter the infamous Dr. Jekylls house. Upon seeing them enter, the doctors 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 doctors laboratory catches fire. The field mice escape, but the house rockets into the sky and explodes into fireworks.