The Secret Serum is the eleventh episode of the first season of Scooby-Doo! Mystery Incorporated.


A vampire is stealing apparently random items, and Daphne suspects her mother is the culprit.


A vampire strikes a charity auction run by Nan Blake and Sheila Altoonian. Apparently able to fly, she steals a worthless scary painting.

The gang is lounging around the swimming pool at Daphne's house the next day. Relationships are not going well -- Velma is angry at Shaggy for breaking up with her, and Daphne is angry with Fred for thinking of nothing but traps. Daphne's mother comes in and tells them about the Vampire's art theft. Fred wants to investigate, but Velma and Daphne are unwilling to come along.

Fred, Shaggy, and Scooby take the Mystery Machine and investigate assorted places they think a vampire might go (the cemetery, a blood bank, etc.). Shaggy and Scooby keep suggesting places with food. Daphne and Velma relax at the Blake mansion, until Mrs. Blake leaves with a lame excuse about shopping for paté. Velma and Daphne try to follow her on foot, but she loses them.

Both groups spot lights on in the greenhouse at the Botanical Gardens. Fred sets a net trap, which only catches Daphne and Velma. After they get the girls free they are all attacked by the Vampire, which steals a rare orchid.

The gang decides to look for vampire information at the Crystal Cove Spook Museum, where Angie Dinkley directs them to her bookshelves on the subject. They find nothing until the agent of Mr. E shoves a magazine to Daphne; it contains a (probably bogus) formula for eternal youth with exactly the ingredients stolen so far, with two more to go.

The next is a rare vintage of wine, which Velma thinks can only be found in the wine cellar of the posh restaurant Crab Net of Dr. Calimari. They disguise themselves as French customers who want to inspect the wine cellar. When that doesn't work, they claim to need the bathroom and sneak into the cellar instead. On the way there they see Nan and Sheila. The Vampire attacks again, steals the wine, and locks them behind a metal door.

The next item is a cursed ruby which is on display at the Darrow University Museum of Oddities. Fred set traps, which go wrong when the Vampire shows up from an unexpected direction. Scooby-Doo manages to bite through the rope holding up a second net and traps the villain. Daphne addresses the Vampire as her mother and threatens to stake her. At this the Vampire pulls off her mask and reveals she is actually Sheila Altoonian. She envies Nan Blake for aging better than she has. She found the magazine article with the formula for eternal youth and set out to steal the ingredients in Vampire guise, so that she could have the eternal youth of a vampire. She propelled herself into the air with her strong leg muscles and glided like a flying squirrel to give the illusion of true flight.

Nan Blake shows up and explains the reason she was sneaking out at night: she was secretly studying to be a notary. Unfortunately she has managed to learn nothing whatsoever about what a notary does, so she is unlikely to pass the final the next day.

After the case is solved, the Mystery Incorporated group sadly go their separate ways. It doesn't look like they will hold together much longer. The sinister servant of Mr. E looks on angrily.


Main characters:

Supporting characters:


Other characters:





Suspect Motive/reason
Nan Blake She went out one evening, with a lame excuse about shopping for paté.


Culprit Motive/reason
Sheila Altoonian as the Vampire To make a youth potion.


Frank Welker Scooby-Doo
Fred Jones, Jr.
Matthew Lillard Shaggy Rogers
Gary Papluta
Grey DeLisle Daphne Blake
Mindy Cohn Velma Dinkley
Frances Conroy Angie Dinkley
Patrick Warburton Sheriff Bronson Stone
Kath Soucie Nan Blake
Beverly D'Angelo Sheila Altoonian
Kevin Dunn Garden manager
Maitre 'd
Tom Kenny Auctioneer
Richard McGonagle Ed Machine


  • TBA


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Cultural references

  • The auctioneer is a parody of David Dickinson, an Engish antiques expert, television presenter, and entrepreneur, who has been the host of BBC's The Antiques Show and Bargain Hunt, as well as ITV's Dickinson's Real Deal.
  • A character resembling Cass Elliot appears in the teaser among the audience at the auction. She guest starred as herself in the The New Scooby-Doo Movies episode, The Haunted Candy Factory.
  • The tourist resembling Don Knotts also appears again, at the auction, bringing a painting on stage.
  • The restaurant's name parodies the title of a famous horror movie: The Cabinet of Dr. Caligari.
  • Angie Dinkley can be heard discussing the whereabouts of an order of Sumatran Rat-Monkeys from Skull Island. In the the horror film Dead Alive (released as Braindead outside of North America) Sumatran Rat-Monkeys are the creatures responsible for turning a significant amount of the Wellington, New Zealand populace into ravenous zombies.

Animation mistakes and/or technical glitches

  • None known.

Inconsistencies/continuity errors and/or goofs/oddities

  • Nan is out in the dark in this episode, although it was previously in implied in The Creeping Creatures that she wouldn't pick up the gang from Gatorsburg because she was afraid of the dark. This may be chalked up to her just lying because she didn't want to.

In other languages

Languages Name Meaning
Spanish (Latin America) La Poción de la Juventud The Youth Potion
Italy La Pozione Segreta The Secret Potion
French L'Élixir du Vampire The Elixir of the Vampire
Portuguese O Soro Secreto The Secret Serum
Hungarian A Titkos Elixír The Secret Elixir

Η Μυστική Φόρμουλα (Star TV Dub)

Ο Μυστικός Ορός (Boomerang TV Dub)

The Secret Formula (Star TV Dub)

The Secret Serum (Boomerang TV Dub)

Home media


Daphne: Velma, here is the only thing you'll ever need to know about boys. They are stupid. If you give a boy two choices, a smart one and a stupid one, he will always make the stupid one. Every time! That's why you never give him a choice.
Velma: That's depressing.
Daphne: Yes, it is. But what can you do? Boys look really cute in ascots.

Shaggy: Freddy. Where do you get this stuff?
Fred: Trapmart. I'm a premier member of the "Frequent Trappers Club".

External links

  • TBA

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Howl of the Fright Hound Scooby-Doo! Mystery Incorporated
Season 1
The Shrieking Madness

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