Velma's got an interview at the prestigious Kingston University, the most selective school in the country. The only catch? The dean wants her and the rest of the Scooby gang to figure out why the ghost of Elias Kingston, the school's founder, is haunting Kingston's book-filled halls!
Fred gets a call for help from Chuck, his daredevil of a best friend, leading the gang on a rescue mission deep in the caverns of an ancient civilization.
The gang climbs aboard the cruise ship run by Fred's cousin despite Velma's strong dislike of water.
The gang visits the set of Scooby's favorite TV show and he meets a dog actress who plays a detective on the screen.
Shaggy takes the gang to the Minor League Baseball stadium of his youth only to learn that it's about to be shut down because a ghostly baseball player is scaring away the fans.
Fred switches places with the tour guide at a history museum to give him a chance to lead the gang in solving a mystery.
To solve the mystery of a creepy Crystal Crawler, the gang must venture into the Crystal Canopy.
The gang play new roles at a murder mystery party.
The gang pretend to be a band to investigate a ghostly musician.
While visiting Shaggy's and Scooby's food mentor, they have to help out in the restaurant while solving the mystery of the yeti attacks.
While the gang was enjoying a tour of a robot factory, a robot butler becomes self-aware and tries to do in all the humans.
Scooby and the gang get arrested by the army, accused of being the aliens that crash-landed in the desert earlier.
Scooby gets an inheritance from a rich man he once saved. But, to collect on it, the gang spend a night in a creepy mansion with the rich man's strange relatives and a spooky phantom.
A pterodactyl terrorizes the town at Christmas as Daphne tries to celebrate her birthday and Fred keeps trying to make the mystery into a Christmas one.
Fred visits a high security prison and ends up investigating the ghost of an escaped inmate who's wreaking havoc on it.
The gang get to ride the first test flight on the biggest plane in the world, the Air Gigantica. They learn of a gremlin trying to destroy this plane and search for it during the flight.
A sorceror takes over a snack factory for a new snack Scooby and Shaggy love, so the gang step in to capture him.
While the gang visits New Orleans (and Daphne pretends to be a vampire), they encounter a Creature from the Black Bayou that's keeping everyone out of the swamp lands.
The gang hits the ski slopes, although Daphne's more focused on nailing Fred with a revenge snowball. Their snowy fun is soon interrupted by the appearance of an evil Snowman Monster eager to scare all trespassers off his mountain.
The gang visit Ireland for a castle Daphne's family just found out they own, and they learn a giant is coming to destroy them all.
The gang visits a farm that is haunted by a creepy scarecrow ghost. Fred wants to impress the farmer's daughter with his skills in mystery solving.
Taking part in a wedding of two close friends, best man Shaggy and maid of honor Daphne try to save the perfect day from being ruined by a ghost bride.
When the gang attends a Day of the Dead festival in Mexico, Fred thinks he can become a legend if he captures the ghost of the criminal El Bandito for the town locals.
A killer clown surfaces at an amusement park. Daphne agrees to babysit her friend's son, which puts a cramp in Fred's mystery-solving.
The gang help campers who are being terrorized by viking ghosts, but Daphne has a plan of her own to earn more Ranger patches.
Fred goes on trial for posing as a rampaging mutant and Daphne serves as his lawyer.
Fred begins to obsessively trap everyone, so the gang decides he needs a break from mystery solving and takes him to Daphne's beach cabin. While there, a walking shark begins terrorizing the area, and the gang attempts to hide this from Fred so he can get some rest.
After Scooby completely loses his appetite, the gang brings him into an old Gothic animal hospital in the woods. Upon arrival, Scooby discovers there is a werewolf haunting the hospital and the gang attempts to solve the mystery while dealing with Daphne becoming a mime.
The gang visits a Renaissance fair per the wish of Velma, who frequented the fair when she was younger. They quickly discover that living in the Middle Ages isn't all fun and games when a jester's ghost tries to close down the fair forever and overthrow the king.
After being brutally beaten up by a monster, Shaggy and Scooby decide to quit the gang and hire replacements for themselves. Whilst providing on the job training for the newbies, Shaggy and Scooby realize replacing themselves isn't as easy as they had thought, particularly when a blood-sucking vampire appears.
When a giant creature called a Houndbeast attacks a dog show, Scooby goes undercover and enters the show to solve the mystery. However, internal struggles between the gang make it difficult to solve the mystery, including Velma and Shaggy switching personalities, Fred pretending to be a rich millionaire, and Scooby trying to earn the respect of the other dogs.
When the gang takes a monster-free vacation on a train, they are shocked to learn there is not only one monster lurking on the train, but eight separate creatures from all over the world haunting the train.
The gang visits a strange town on Halloween night to celebrate the holiday, but the festivities are soon interrupted when Shaggy and Scooby run into a witch's house while trick or treating. Much to the gang's surprise, Fred reveals that he ran into this same witch 11 years ago and has been afraid to solve a mystery on Halloween ever since. In the process of solving the mystery, the gang tries to convince Fred that it is possible to solve a mystery on Halloween night despite his superstitious belief.
Velma takes the gang on a visit to Japan after she is invited there by a friend, but they soon discover that the city is being haunted by a crab monster named Kaniaku. Meanwhile, Daphne goes viral in the Japanese media.
After the ghost of the town of Littlefield's founder scares the other mayoral candidate off from running, Velma takes his place, but she soon discovers that what the voters are looking for may not always be the complete truth.
The gang is in Britain for Velma's symposium speech on Christmas Eve, but the spirit of mystery is in the air when they meet a man who claims he will be haunted by three ghosts. While Scrooge's lack of articulateness and Fred's grudge against raccoons keeps the gang occupied, Velma discovers that the ghosts are not only there to show Scrooge the error of his ways. It seems the ghosts want to show her that her life would be far better without being oppressed by the gang's obsession with mysteries.
After mistakenly parking on a spaceship's loading dock, Fred and the gang are sent in space where a virus turning people into skull aliens is rapidly spreading. The gang has to figure a way to solve the mystery and avoid becoming contaminated with the alien virus.
Stuck in a snowstorm, the gang stays at The Good Son Inn, where the hotel owner is oddly strict about his rules. The gang later discovers that the reason for this is because the owner's dead mother will give a terrifying scolding to anyone who does not follow her rules.
While the gang is touring Fletcher Studios, they discover that a remake of a never-before-seen Archie Barnes silent film is in the process of being made. However, what they don't realize is that Archie Barnes has returned from the grave to prevent his last unfinished film from being seen.
The gang visits the Hocus Pocus Magician's Club and Fred attempts to join the club as a magician, under his persona Freddy Or Not. After Fred's first performance at the club is ruined by a mutant rabbit, the gang attempts to solve the mystery.
While trapped in an Ancient Grecian building with the ceiling slowly closing in on them, Velma finds an old scroll. This leads to both their escape route, and a story about one of the first mysteries in Ancient Greece, involving the gang as Ancient Grecian citizens and a spider monster.
Shaggy inadvertently runs into his first crush, Amelia, who he discovers has decided to become a goth. Worried his personality isn't exciting enough for her, Shaggy decides to adopt the goth subculture. During Shaggy's "Goth Initiation," a plant monster attacks the goths' hangout. While the gang becomes focused on solving the mystery, Shaggy realizes that being a goth isn't a way to hide to his true self from others, but instead a way of expressing one's true self.
The gang meets British secret agent Jenny Vex, who attempts to enlist them in her mission of saving the world. It seems the supervillain Bubby has a dastardly plan to forever end the meal of breakfast, and has sent another secret agent, Minus, after Jenny and the gang. The gang has to trade their detective caps for spy gear in order to stop the supervillains from permanently eliminating breakfast from the menu!
When the gang returns to Velasco, where they had previously solved a mystery, they discover there is yet another mystery in the town. The five friends have to solve their most difficult mystery yet when an evil force possesses the Mystery Machine and tries to hunt the gang down. While the gang flees for their lives, Fred goes through intense denial about his beloved van.
Daphne takes the gang to an Ice Hotel, where a caveman frozen in ice was recently discovered. While Daphne is acting very peculiar, the Ice Man thaws out and goes on a rampage around the hotel. The gang has to solve yet another mystery, while contending yet again with Velma's extreme fear of water (in all its forms) and Daphne's very strange behavior.
The gang drives to Florida to see Shaggy's grandmother who is in a nursing home there. Worried that his grandma will be disappointed in him, Shaggy pretends he is leader of the gang and Daphne is his girlfriend. However, as always, the gang has to solve another mystery, though none of them are sure which is more upsetting: the Ape Man running around the nursing home or the horrific shorts Fred is wearing to keep him cool.
Fred brings the gang to the local garbage dump to find a rare part for the Mystery Machine, inadvertently resulting in Scooby running into his old kennel mate Axel. After Axel acts very coldly to Scooby, he and Shaggy become determined to solve the mystery of the Trash Monster, which Axel is also trying to capture. Meanwhile, Daphne tries to become exactly like Fred to find out how he feels as the leader of the gang.
Velma is offered 10 million dollars by the Brainsplosion company, who wants to use a video game code she made with her friend Zara for the sequel to their successful game Protein Titans. However, Velma is forced to make a very difficult decision when the company offers her a five-year contract. Meanwhile, the rest of the gang attempts to solve the mystery of the Ghost Chef, the villain from the Protein Titans game, who has suddenly become real.
The gang visits Salem, Massachusetts to go to a historical festival, but quickly after they arrive, the events of Salem Witch Trials begin repeating themselves. A legendary demon, supposedly conjured by a woman accused of being a witch, has returned to Salem to seek vengeance on the townspeople. Fed up with the prejudice witch stereotyping, Daphne speaks out against the mayor of the town, causing her to be accused of witchcraft herself.
Fred and the gang are requested to help solve the mystery of the escaped villain Professor Huh?, but they soon run into Fred's childhood friend, Rose, who acts very aggressively towards him and is trying to compete against the gang to solve the mystery first. To make matters worse, Professor Huh? is notorious for not leaving any clues and being as elusive and confusing as possible. The gang tries to solve their most difficult mystery yet, while learning something shocking about Fred in the process.
Fred's old friend Rose makes the gang prime suspects in the Professor Huh? escape, and they are forced to flee from the police. After narrowly escaping from a rocket and Professor Huh?, the gang attempts to go incognito in order to solve the mystery. A high-speed chase from the police quickly ensues, and the gang realizes that the Professor Huh? mystery goes much deeper than they could have ever imagined.
The gang goes to an arcade which Shaggy frequented in his childhood, so he can finally get Pizza Pup, a stuffed dog prize that he has been desiring since he was a kid. However, what they don't realize is that the arcade's deactivated robotic mascot, Pizza O'Possum, has come to life and wants to frighten everyone away from the arcade.
Fred takes the gang to a seafood restaurant. Their plans for a much-needed relaxing dinner abruptly end when they discover their waiter is none other than Captain Cutler, a previous villain who has eluded them. It seems though, that Captain Cutler has changed his ways, when he requests their help in capturing Half-Beard, a ghost who is scaring all the customers away from Cutler's restaurant.
