Mano Negra sends a group of alien dwarves led by Aker to the state laboratory to kidnap the professor Arego and obtain the formula for the cultivation of microorganisms. The formula is divided among his four daughters and most work at a circus. The aliens take capsules that make themselves invisible, kidnap the girls and are eventually revealed to be blue-skinned, red-eyed monsters who are reduced to a puddle of green goo when killed.