Scooby-Doo and Shaggy win an all-expenses-paid stay at WWE City to watch WrestleMania after beating the hardest level of the organization’s latest video game. At the insistence of the duo, Fred, Daphne, and Velma agree to join them on the trip to WWE City. Upon their arrival, the Mystery Machine crashes on a ditch after Fred narrowly avoids a crossing raccoon. The gang meets John Cena, his trainer Cookie, and Cookie’s nephew, Ruben, before Cena lifts the Mystery Machine back on the road. They also encounter Bayard, a hunter who despises WWE for building their city in his forest. Cena gives the gang VIP tickets to the next event to make up for their altercation with Bayard.
At the show, Mr. McMahon unveils the WWE Championship belt, which has been held vacant since Kane’s last match was overturned. The title is up for grabs over the weekend at WrestleMania. The gang is then offered a tour of WWE’s training camp before arriving at their cabins. Later that night, Daphne and Velma overhear Ruben arguing with Cookie over not becoming a WWE wrestler because of Cookie’s leg injury. Meanwhile, Scooby has a dream about wrestling giant food monsters when Shaggy wakes him up and they both encounter a monster called the Ghost Bear before running for their lives. The WWE wrestlers intervene during the chase, but Triple H and Brodus Clay are overpowered by the monster, which disappears after throwing Sin Cara’s hot rod toward a water tower. The next morning, the gang is briefed by WWE executive Ms. Richards that the city has been terrorized by bear attacks over the past few weeks. Mr. McMahon asks the gang to solve the Ghost Bear mystery to ensure the security of the WWE belt. Cena and Sin Cara explain to the gang that the legend of the Ghost Bear started over 100 years ago with a wrestling bear named Vicious, who was defeated by Sin Cara’s great-great-great grandfather Sin Cara Grande at the grounds that would be WWE City. Furious over its loss, Vicious vented its frustration on the town until Sin Cara Grande warded it off to a cave at the cost of a career-ending leg injury. It is believed by Sin Cara that the spirit of the bear has been stirred by WrestleMania.