The voices of Scott Innes and Frank Welker star in this animated adventure which sees the Mystery Inc. gang reunite after a break from solving mysteries to take on a brand-new investigation involving a ghostly pirate. After a period of going their separate ways, Fred (Frank Welker), Daphne (Mary Kay Bergman), Velma (B.J. Ward), Shaggy (Billy West) and Scooby-Doo (Scott Innes) come together again when Fred and Daphne's TV show about mystery solving needs some new content. The gang travel to the Deep South, where they meet a girl named Lena (Tara Strong) who tells them about the legend of a pirate named Morgan Moonscar, who haunts an island that is now known as Moonscar Island. The team take the ferry to the island, and launch into an investigation, but as they explore the island and quiz the locals, they encounter zombies who may be evidence of some unexplained disappearances that occurred hundreds of years before.