Scooby-Doo: The Mystery Begins is the sequel to Scooby-Doo: Terror of the Ooze. In this film, Fred and Daphne are along with Shaggy, Velma, Shaggy's mom, and their pet dog, Scooby-Doo. After an incident where Shaggy was possessed by the ghost of Scooby-Doo, a friend of Velma's, the three are sent to a beach house by the ghost to hide from the rest of the gang. Fred and Daphne discover a secret room in the house where they find a stuffed ghostly Scooby-Doo.
As Scooby-Doo becomes more crazy and violent, the three investigate a murder in order to determine who the murderer is. They also learn that Scooby-Doo's dad, who's been sleeping for a few days, is now back. Fred, Daphne, and Shaggy finally begin to think they might need a pet, so they bring Scooby along for the ride.
Scooby-Doo: Mystery Begins also includes various other characters from the first film as well. They include Bonnie and Clyde, Bumblebee Man, while also includes their evil henchmen, Scrappy Doo, Beetle, and Beetlejuice. Together they form a team called The Mystery Incorporated.
The plot of the movie is basically as follows, all of the super heroes seem to be out for Scooby-Doo's blood, so he and his new friends set out to stop them from carrying out their crime spree. The main antagonist in the movie is Master Parasite, who does not think the gang can be trusted, since they have been possessed by the ghosts of Scooby-Doo and Shaggy.
For instance, Shaggy has given up being Shaggy, and has instead begun dressing up like Batman, and Velma has gone from wearing one of her old "Pinky Pants" costumes to become the rest of the Scooby Gang. Also, Scooby-Doo's mom has changed into a larger ghostly form. Master Parasite starts by stealing money from the restaurant, but is then foiled by Velma.
While the new Scooby-Doo and his friends are fighting off Master Parasite's minions, we see the original movies from our three-dimensional perspective. For instance, we see what it looks like when a ghost Scooby-Doo uses goes after an unsuspecting citizen.
Some of the additional scenes included in the movie were the following: a cameo appearance by Mr. "What's a Whale," a visit from Santa Claus, and a brief cameo by Scooby and his friends playing a real game of Chutes and Ladders. The addition of these scenes makes the story even more interesting. The actors in these scenes were likeable and well liked.
Overall, this movie was a good watch. It wasn't bad, but some scenes could have been improved upon. The action is great, and the cast was likeable and easily recognized.