Robi goes on the blink during the eve of an all-important mansion housewarming party, forcing Scooby and Shaggy to replace him with a new robot butler. Little do they know, the new "ro-butler" is actually a terminator-like annihilator-bot built by Dr. Phineus Phibes. After Scooby and Shaggy repeatedly frustrate the robot, Dr. Phibes gives the order for a full-on assault. By using a Scooby Snack that gives Scooby transforming battle-bot capabilities - and with the help of Robi, who has been sequestered in a closet- Scooby and Shaggy fight back. In the end, they save themselves from being expelled from the neighborhood; manage to make Mr. Havansimp, the President of the housing association, a foot taller; and, in the meantime, throw the best party in history.