Scooby Doo on Zombie Island

Weight Gain
Daphne is on a talk show to promote her mystery-travel series, Coast to Coast with Daphne Blake, during which she tells the hostess, Chris, about a past Mystery Inc. case when she was younger. At a faraway castle, Shaggy and Scooby are shown to be chased by a large moat monster. The gang had all been previously searching the castle for clues. As Scooby comes crashing down on the monster, the monster is discovered to be Mr. Beeman, a real estate agent. Beeman had been printing counterfeit money. Daphne explains how it was one of her most frightening mysteries. She also discusses her new show in which she plans to find real monsters.

Scooby and Shaggy have taken up work as contraband security guards at a local airport. Unfortunately, they are exposed to a lot of tantalizing foreign food and are unable to resist eating all the contraband. As a result, they are fired from their job.

Fred secretly contacts Velma, who is now a book shop owner, about going on a big trip for Daphne's birthday. Fred also secretly contacts Shaggy and Scooby. He picks them all up on the way to Daphne's home. Daphne is surprised to find the whole gang all with Fred. He explains how they can all search for ghosts together just like old times.

The gang decides to go to New Orleans for the first segment of the television program. They meet up with many fake ghosts such as a floating ghost, which was just a video projection, a vampire bat, who was just an old man stealing a necklace, a ghostly casino riverboat captain, who was really an old lady, and lastly a lobster-man in a factory, who was really a middle-aged man. Daphne is very disappointed to not find a real ghost. As Scooby and Shaggy look for food from local shops, Daphne, Fred, and Velma meet a young chef named Lena. Lena had overheard Daphne's disappointment and says that a real ghost named ​Morgan Moonscar​ haunts the island she works at. Velma looks up the island on her computer and agrees that there had been many strange disappearances on Lena's island. They agree to follow Lena back to her island.

The gang all express their excitement about visiting the island on the car trip down to the ferry. Real ghosts, homemade Cajun food, and the beautiful scenery. The gang meets Jacques, the ferry driver for Moonscar Island, and they board the ferry. Fred begins to videotape the bayou and Jacques discuss how pirates used to use the bayou to hide from the law, including Morgan Moonscar. Soon, Scooby and Shaggy accidentally fall off the ferry trying to catch a catfish named Big Mona. Alligators chase them, but they are rescued by an angry fisherman named Snakebite Scruggs and hunting pig Mojo. Shaggy and Scooby board the ferry again. They reach Moonscar Island and drive off the ferry. Jacques leaves back toward New Orleans. As the gang approaches Simone's house, who is the owner of the plantation Lena works at, they notice all the cats around the porch area. Scooby chases the cats and causes a big commotion, angering Beau the gardener and Simone the house owner. Daphne introduces herself to Simone and they discuss the plantation and its ghosts. Simone agrees that it is haunted by “restless spirits.” She agrees to Daphne recording around the plantation. They all enter the mansion except the cats and the gardener.

Scooby and Shaggy give the rest of the gang a scare after screaming loud. They had simply been surprised by how hot the plantation's peppers were. After Simone, Lena and the rest of the gang leave, Scooby and Shaggy scream again but this time it is because of ghostwriting on the wall that appeared suddenly. Daphne excitedly tapes the wall and another word appears while taping, carved into the wall suddenly. Viewing the tape later in slow-motion, the gang discovers that the writing was done by the ghost of Morgan Moonscar. Scooby and Shaggy get hungry and make a huge picnic basket of food. Velma returns to the wall to see what is under the wall paint. She uses a spatula to peel off all the paint behind the ghostly words written by the ghost. She discovers a piece of Morgan Moonscar's ship which was used in the construction of the mansion. Simone and Lena aren't surprised.

Scooby and Shaggy get into mischief with Simone's cats and Mojo the hunting pig. They fall into a hole, which they later discover is a grave. As they try to exit the grave, they pull off a piece of the wall and a skeleton hand falls from a hole in the side of the wall. Above them, a sinister-looking green fog-like energy manifests and envelopes the entire skeleton. It begins to gain skin, clothing and hair, and morphs into the zombie of Morgan Moonscar himself, and it begins to chase Scooby and Shaggy who escape the grave and run for their lives. They run into Beau the gardener but can't find the zombie afterward. The gang goes back to investigate the grave but it is found to be empty. It starts to get dark and Simone offers for the gang to stay at her home for the night. They agree.

Lena quickly but kindly shows the gang around to their individual rooms. Shaggy, who is excited about dinner, gets dressed and trims his beard. Scooby plays with an owl just outside the window. As Shaggy stares into the mirror, a Civil War ghost comes out of the mirror and tries to warn Shaggy telling him to “get away”, just as the ghost of Morgan Moonscar had tried to warn the gang by his message in the kitchen. Velma investigates the mirror and agrees that it is from the Civil War era. Everyone leaves for dinner. At dinner, Scooby causes trouble with the cats again. He and Shaggy have to eat a crawfish boil outside in the Mystery Machine. They enjoy the Cajun meal until the cats follow them to the mystery machine and all stare at them through the windows. Shaggy drives the Mystery Machine away in order to shake off the cats. Meanwhile, Fred, Daphne, and Velma discuss over Simone's dinner table why someone in a pirate mask would want to scare everyone off the island. Treasure? Lena served a big meal, Fred, Daphne, Velma, Lena and Simone ate a lot of food, They gained a lot of weight until they got Big and Fat. Later back at the Mystery Machine Both Shaggy and Scooby gained a lot of weight until they got Big and Fat. The same green light hit both the ground and water, The Zombies came out both the ground and the water, Fat Shaggy and Fat Scooby got scared and drove off but they Ran into Jacque who revealed himself as a Cat Creature