When Velma's uncle Dave goes missing, the gang attempts to find him. On their search, the gang is attacked by the legendary Willawaw, which is said to capture people if an owl calls their name.
While on a boat flowing down the Gulf Stream, the gang witnesses a flying saucer hijacking an airplane. They crash on Diablo Island, where they discover a spooky-looking sea captain and a trio of one-eyed and skeleton extraterrestrials.
After being invited by Professor Krueger to the North Pole, the gang finds out he has been captured by a terrifying Antarctic dinosaur-like monster.
The gang travels to Salem to visit a friend, Arlene Wilcox, on Halloween night. However, the town is being haunted by a witch, and the townsfolk suspect Arlene, who is a descendant of the witch in question, and sets out to get a confession from her.
The gang encounter a tar monster on a visit to an archaeological site in Turkey.
The gang travels to Scotland to visit their friend Aggie MacDuff, whose family castle is being plagued by the ghost of her great-grandfather, who lures the Loch Ness Monster with his bagpipes.
As the gang goes water-skiing, they have a near-fatal encounter with a masked figure and his sharks. When they visit a cafe, they find out that the figure is Old Iron Face, a convict with an iron mask welded onto his face.
After an emergency plane landing in the Amazon jungle in Brazil, the gang encounters the Jaguaro, a terrifying creature with the head of a black Smilodon and the body of a gorilla.
Scooby, Shaggy, Daphne, Velma and Fred try to uncover the mystery behind the strange appearance of a cat creature who has been robbing jewellery shops in the area.
While visiting Professor Greer's botanical gardens, the gang encounters a seven-foot mantis who is trying to scare the professor away.
The gang goes to the Decade Records recording studio to see a live recording from their friend Jimmy Lewis. However, when songwriter Tony Synes disappears and a ghostly musician begins searching for his latest song.
While stranded in a palace in Rampoo in China, the gang stays with Kim, who is about to receive a large inheritance. When the gang goes to sleep, they are awakened by the Moon Monster, a strange creature who can turn people into stone if his shadow falls on them.
In Venice, Italy, the gang meets their friend, Antonio. They soon discover that a new ghost is haunting their friend and head out to solve the problem.
The gang visits a fortress in Puerto Rico, where they find the ghost of Spanish general, Juan Carlos, who warns the gang to stay away from his fortress territory.
In England, the gang meets up with tennis star Jimmy Pelton, who has been cursed by a warlock known as Anthos. The gang agrees to solve the mystery for Jimmy, but it appears they too may be cursed by Anthos.
The gang's fishing trip is disrupted by a beast who has scared everyone away from the village of Bottomless Lake