Professor Poisson, a world-renowned oceanographer, is on a quest assigned to him by the museum to go and retrieve artifacts from a sunken ship named the Diablo Doro. Along with him, is Mystery Inc., Shaggy, Scooby, Daphne, Velma and Fred. They are boarded on a ship named the Sea Prowler. But the boat's operator, Mr. Carp, warns the professor and the gang that Diablo Doro is guarded by the ghost of Captain Pescado and his sea monster crew. The professor tells the kids these are just stories, and then informs the captain that they are over the Diablo Doro. They drop anchor and go to bed. That night, Scooby, Freddy and Shaggy see Captain Pescado's ghost, a kelp monster, and an octopus monster outside their window in the ocean. He informs the girls and they go on deck to check it out. There, they find wet footprints leading onto the boat. Suddenly, Captain Pescado appears as well as the Kelp Monster, appears and chases the gang. They run into Professor Poisson and warn him. Mr. Carp and the deck hands board a life boat and decide to row to port because of the ghosts.
The next morning, the gang finds the professor's cabin ransacked, and Professor Poisson vanished. On the floor, is a secret code with the letter "IMCMMSC", their first clue. They decide to look for Professor Poisson. Scooby and Shaggy go into the galley and get locked inside by the octopus. Daphne, Velma and Fred get locked inside a room but manage to escape through a ventilation funnel. They look for Shag and Scoob, but get separated and Velma gets locked in the engine room. She climbs out through the smokestack where she is able to see the life boat that the the captain and the deck hands got in. The gang reunites and discovers the life boat is empty and battered, covered in kelp and wet footprints. They split up, Velma, Shag and Scoob go to the radio room to try and send a distress signal, and Fred and Daphne try to find the professor. Velma, Shaggy and Scooby send part of a distress message using Morse Code, but in doing do, they alert the kelp monster and the octopus. The two aquatic goons chase all three of them. Fred and Daphne witness Captain Pescado diving back down to the wreck and then meet up with Scooby, Shaggy and Velma.
Shaggy, Scooby, and Velma equip scuba suits and dive down to the Diablo Doro and upon entrance, they discover air tanks, what does a ghost and sea monster need with scuba tanks? Scooby accidentally smashes through an old wall, and finds a treasure room-and the ghost and the sea monsters! Velma, Shaggy and Scooby are chased back up to the Sea Prowler. There they find the villains have gotten there first, and shoved Fred and Daphne into a closet. The ghosts then jump back into the water and they lift the submarine back into the hole, preventing the monsters from getting aboard. Velma explains that they must be taking the treasure from the wreck and hiding it on-board. With the help of metal detectors, they find the treasure locked up in the brig, along with a bound Professor Poisson. The try to go radio for help, but Pescado, the Kelp Monster, and the octopus climb on board via ladder and chase Velma, Daphne and the professor and Fred, Shaggy and Scooby manage to trap Pescado and the sea goons in a net. The Ghost of Captain Pescado is unmasked as Mr. Carr, and the Kelp and the Octopus Monster are unmasked as the deck hands. The scribbled note "IMCMMSC" is wrong. The I is a 1! 1MCMMSC. 1MC stands for First Mate Carp and MM means McFinn and McGil, the two deck hands. The SC meant Professor Poisson was trying to write scuba divers before he was attacked. Mr. Carp was trying to steal the treasure from the wreck and haul it back on board, the air tanks that Velma, Scooby and Shaggy saw proved that the ghosts-weren't ghosts. The Coast Guard arrives to arrest the three criminals.
Scooby gets a laugh from wearing the treasures from the Diablo Doro after Shaggy calls hims the "six million dollar dog".
Cast and characters
|Casey Kasem|| Shaggy Rogers|
|Frank Welker|| Fred Jones|
|Heather North||Daphne Blake|
|Patricia Stevens||Velma Dinkley|
|John Stephenson|| Professor Poisson|
Ghost of Captain Pescado
- Ghost of Captain Pescado/Mr. Carp
- Kelp Monster/Mr. McFinn
- Octopus Monster/Mr. McGil
| Mr. Carp as the Ghost of Captain Pescado|
Mr. McFinn as the Kelp Monster
Mr. McGil as the Octopus Monster
|To steal treasure from the sunken ship.|
- Many of the characters that are in this episode have names that are related to fish:
- Carp is a type of fish
- Gil (although spelled Gill) is what lets a fish breathe underwater
- Finn (although spelled Fin) is what lets a fish move easier underwater
- Pescado is Spanish for fish
- Poisson is French for fish
- Velma learned morse code in the girl scouts.
Animation mistakes and/or technical glitches
- For a moment when Carp is unmasked his hair is black instead of brown.
Inconstitencies/continuity errors and/or goofs/oddities
- When the gang finds the professor's cabin ransacked, and Professor Poisson vanished, Daphne says "creepers" instead of "jeepers", her normal catchphrase.
- The Scooby-Doo!/Dynomutt Hour: The Complete Series DVD set released March 7, 2006.
There's A Demon Shark In The Foggy Dark
The Ghost that Sacked The Quarterback