Scooby Doo! The Mystery Begins

ScoobyDoo The Mystery Begins is a 2009 American television film comedy fantasy and adventure film directed by Brian Levant, produced by Warner Premiere and distributed by Warner Home Video. The film was aired by Cartoon Network on September 13, 2009, the 40th anniversary of the HannaBarbera character ScoobyDoo, and later released on September 22, 2009 on DVD and BluRay. It is the third installment in the ScoobyDoo liveaction film series, serving as a prequel to the 2002 and 2004 theatrical films acting as an origin story for Scooby and the Mystery Inc. gang, revealing how they met and the events of their very first case. Although the film was placed prior to the events of the original ScoobyDoo series, ScoobyDoo, Where Are You, the time frame has been advanced to the present day.

In Coolsville, Ohio, four teenagers are involved in a fight on the school bus and are sent to detention. Norville Shaggy Rogers is a clumsy, geeky outcast, who tried to smuggle his dog ScoobyDoo onto the bus Fred Jones is quarterback of the football team Velma Dinkley is a science nerd and Daphne Blake is in the drama club. They bond somewhat over a shared interest in mysteries, but quickly get on each others nerves. While in the library for detention, two ghosts appear and chase them to the gym where a pep rally is going on. A third ghost, The Specter appears, causing the lights in the building to flicker. He starts telling everyone to leave. The stampcollecting Principal Deedle decides to close the school, but Vice Principal Grimes deems it a prank and suspends the quartet.The gang tries to clear their names by investigating the ghosts, which leads to Grimes expelling them. Further investigation, in disguise at the school, makes them think Grimes is their prime suspect. Searching at night at Grimes house leads them to information about a time capsule. The ghosts attack again, and the teens are knocked out. The Specter, keeping Scooby and Grimes as prisoners, forces the gang to search underground for the time capsule. Unable to find the capsule, they trick the Specter into coming down to carry the capsule out of the hole, but the plan backfires when they try to lock him up in a flooded room, and the Specter acquires the capsule. ........

Source: Wikipedia