The islanders turn out to be more suspicious than helpful. Some are hiding secrets tied to Roux’s revival. The gang uncovers that Lena and others have knowingly used Roux’s recordings and voodoo artifacts to engineer the zombie attacks as part of a plot to scare people away and keep the island’s secrets, or to gain power and wealth. A climactic showdown in the ruins of Roux’s house and the swamp pits the gang against both the living conspirators and the undead. Fred, Daphne, Velma, Shaggy, and Scooby use traps, quick thinking, and courage—Shaggy and Scooby playing key roles—to disrupt the ritual and turn the tide.
The film assembled an incredible voice cast of established talents and rising stars. While most original actors were replaced, returned as Fred Jones. The new voice for Scooby-Doo was Scott Innes , a voice actor and radio personality known for his performances in later Scooby media. Billy West took over the role of Norville "Shaggy" Rogers. The rest of the Mystery Inc. was rounded out by Mary Kay Bergman as Daphne and B.J. Ward as Velma. Scooby-Doo on Zombie Island
The movie's success also paved the way for future Scooby-Doo productions, including the popular Scooby-Doo! Mystery Incorporated series, which debuted in 2010. The film's influence can also be seen in more recent animated series, such as Gravity Falls and Adventure Time , which have borrowed elements from Zombie Island 's blend of mystery, adventure, and humor. The islanders turn out to be more suspicious than helpful