There they meet Glenn, a rookie detective and the police chief's son, who was convinced by Marilyn to help them clear their names.
Herman and Grandpa dress up as waitresses and infiltrate the pizzeria and wait until the owner meets up with an accomplice and leaves.
Grandpa injects the serum into Igor, causing him to live and become young enough to where he won't be killed by angry villagers.
Herman and Grandpa make it back home just before Halloween where a number of relatives have arrived for the celebration.
A very high note from Cousin Phantom eventually breaks the container allowing Marilyn, Glenn and Herman to meet Grandpa at the museum.
Grandpa administers the serum to the mummy while Marilyn steals the controller, rendering the robots useless.