A mysterious criminal steals a secret state-of-the-art time machine, intent on destroying America as we know it by changing the past. Our only hope is an unexpected team: a scientist, a soldier and a history professor, who must use the machine's prototype to travel back in time to critical events. While they must make every effort not to affect the past themselves, they must also stay one step ahead of this dangerous fugitive. But can this handpicked team uncover the mystery behind it all and end his destruction before it's too late?

Scooby-Doo and the Mystery, Inc. gang are launched into the 21st century, with new mysteries to solve.