Scooby-Doo ! The Mystery Begins is the prequel to two other films .
It is the third ( chronologically , the first ) installment in the Scooby-Doo live-action film series , the film is a prequel to the first two films , which depicts how Scooby and the Mystery Inc. gang met and the events of their very first case .
Scooby-Doo! The Mystery Begins