Scooby Doo! Who's Watching Who? is great animated action with Scooby and the gang. Mystery,  Inc. is facing one of its toughest cases -- and it's got less to do with ghosts than with  their rivals. A new team of ghost hunters called GSI (Ghost Scene Investigators) is out  there, competing with the gang. They'll have to race them to unmask a series of classic  ghosts, while travelling cross-country.