 Marilyn s at the museum making an school report. Lily asks Herman to pick her up, but before he will take an experimental sleeping pill, invented by Grandpa. The pill has a clock, which can be set for the number of sleeping hours. Grandpa sets the pill for nearly 10 hours. Herman arrives late to the museum and he got stuck inside. Searching for an opened door, Herman will find a rare Egyptian sarcophagus, studied by two specialists of the museum, whom believe belongs to King Tuth IV. But Herman believes that the sarcophagus is actually a phone boot. When he tries to make a call inside of the sarcophagus, accidentally he shuts himself up. Under the effects of the pill, Herman falls asleep inside of the sarcophagus. Lily s worried about Herman, and she believes that Herman has goofed again. Eddie sees in the paper the notice about an ancient mummy, with a picture of Herman sleeping inside of the sarcophagus. The scientists believes that Herman is the mummy of Tuth IV, the discover of the year. But Lily goes to the museum and claims to the scientists that the mummy is her husband. Confindently, Lily says her address and asks for the scientists that when Herman wakes up give him two dollars, so he can take a taxi to return home. The scientists believes that Lily s crazy and doesn t care about what she says. But later, Herman wakes up and scares the scientist assistant. At home, Herman asks Grandpa for another pill, because of the great results, but this time with less sleeping time. The scientist arrives with the police to the Munsters  house and demands Lily to tell where s the mummy. Lily says that there s no mummy and that they can see for themselves in the laboratory. Herman s sleeping peacefully in the laboratory, and the police takes him away. Grandpa and Lily aren t worry about Herman, because in a few minutes he will wake up. After hearing a mother-in-law-joke from one policeman, Herman wakes up laughing inside of the museum van, scaring the scientist and the policemen.