From Movie Insider, here's the official summary from Warner Brothers for the upcoming animated Scooby-Doo movie "S.C.O.O.B.":
Since the beginning of time, an epic battle has waged between humans and ghostly forces of evil, and only the spell of a powerful canine warrior can keep the spirits at bay. When the spell begins to weaken, S.C.O.O.B. – an elite group of heroes comprised of the most beloved Hanna-Barbera characters – recruit Scooby-Doo to find the enchanted collar that is the key to stopping the impending ghost attack. Together with his new group of allies and the original Mystery Inc. gang, Scooby-Doo embarks on the ultimate adventure to save man (and dog) kind!