After solving the mystery of the Ghost Bear, Mystery Inc. is seen at
WWE's latest event, The Muscle Moto X Off Road Challenge, an off-road race for WWE superstars with bountiful
prize money.
Scooby-Doo and
Shaggy Rogers are there working at a
food truck. Many WWE superstars are in the race, including WWE chairman
Vince McMahon's own daughter
Stephanie and her husband
Triple H. Scooby and Shaggy are excited to hear that
The Undertaker is going to be in the race. A
demonic racer known as Inferno later appears to sabotage the race. Shaggy and Scooby try to run away with the food from their truck, but before they can, McMahon hires Mystery Inc. to solve this mystery and intends to keep Stephanie out of the race, but she refuses.
Daphne Blake becomes friends with Stephanie after they learn about their respective families' wealthy patriarchs, making
Velma feel very left out. Undertaker is disappointed that his partner,
Dusty Rhodes, was injured in the race and recruits Shaggy and Scooby to be his new partners under the names "Skinny Man" and "Dead Meat", to which they reluctantly agree to at first. However, since Undertaker's race car was also destroyed in Inferno's attack,
Fred Jones modifies Shaggy and Scooby's food truck into "The Scoobinator" to replace it. During the first race, Inferno attacks and Velma, Daphne and Fred notice that McMahon is nowhere to be seen. That night, Scooby and Shaggy are chased by Inferno only to be saved by
The Miz. The following morning, Inferno attacks again and Scooby, Shaggy and Undertaker almost drown when The Scoobinator lands in water, but the trio are able to escape in the nick of time. That night, Daphne tells Velma even though she enjoyed hanging out with Stephanie, Velma will always be her best friend. The following day, Fred modifies the
Mystery Machine to replace The Scoobinator as he, Daphne and Velma join as additional passengers. Inferno attacks once more and goes after the gang, only for the other WWE stars in the race to gang up on Inferno and attack his race car with theirs as Undertaker takes on the villain. They figure out that he is using radio technology to operate his race car so they create a
remote control that disrupts his signal and puts them in control of the vehicle. Following Inferno's defeat, he is revealed to be Triple H, who had been plotting to win the race by any means necessary, with Stephanie mostly masterminding the plot on account of being furious at McMahon for preventing her from qualifying due to being concerned about her well-being. Even after her father apologizes for his mistake, Stephanie is apprehended for her and Triple H's crimes nonetheless. Soon after, Scooby, Shaggy and Undertaker win the prize money by default. ==Voice cast==