Feature-length animated adventure following Scooby-Doo (voice of Frank Welker) and the Mystery Inc. gang as they investigate another mystery. After retiring and selling the Mystery Machine, the gang is contacted by Vincent Van Ghoul (Maurice LaMarche) and tasked with finding the missing 13th ghost. Their quest takes them to the Himalayas, where they race to find the chest of demons before their ghoulish adversary. After briefly enjoying retirement, how will Scooby, Shaggy (Matthew Lillard), Velma (Kate Micucci), Daphne (Grey Griffin) and Fred (Welker) cope with being back in business?