When the Mystery Inc. gang is invited to Spooky Island, a popular amusement park, they soon discover that the attractions aren't the only things that are spooky. Strange things are happening, and it's up to Scooby, Shaggy, Fred, Daphne, and Velma to uncover the truth behind the mysterious happenings.

The Mystery Machine is stuck in Nowhere, leading the gang to seek help from Courage and his family.

After going their separate ways, Scooby-Doo, Shaggy, Velma, Daphne, and Fred reunite to investigate the ghost of Moonscar the pirate on a haunted bayou island, but it turns out the swashbuckler's spirit isn't the only creepy character on the island. The sleuths also meet up with cat creatures and zombies... and it looks like for the first time in their lives, these ghouls might actually be real.