Scooby Doo and KISS in the same movie? Damn right! We see Scooby-Doo, Shaggy, Daphne, Velma and Fred traveling to a Kiss themed amusement park called Kiss World to see Kiss at their big Halloween concert and solve a mystery, mostly because Daphne has a crush on Paul Stanley A.K.A Starchild, much to Fred’s jealousy.
After Scooby and the gang arrive, security guard Delilah Domino refuses to let them in. So they sneak in and are caught by Delilah. However at that moment Kiss arrives and after the gang explains that they’re here to help, they tell her the kids are free to stay. However Gene Simmons A.K.A The Demon is against Scooby and the gang staying, because when Scooby and Shaggy first saw him, Scooby squirted him with a water gun.
Soon Shaggy and Scooby are chased by a scary witch, luckily Kiss comes to their aid. They tell the gang that the witch is called the Crimson Witch and she has been terrorizing the park for a while and they need her gone before the concert. A strange woman named Chikara says that the witch is from an alternate universe called KISSteria and plans to use the black diamond that Kiss uses in their song Detroit Rock City to summon a monster called The Destroyer to destroy the earth, which Velma finds hard to believe. The gang must stop the witch. They grab the diamond and use it trap the witch.
However the witch chases them through a portal to KISSteria to get the diamond. She manages to gets it and unleash The Destroyer, but the gang and Kiss arrive to stop The Destroyer.
While Kiss rocks out at their concert, Scooby and his friends use a spaceship to kill The Destroyer. After The Destroyer is defeated, Scooby and the gang return to earth and unmask the witch who is really Delilah who says the diamond was a priceless diamond.
Later, Starchild gives Daphne a kiss right in front of Fred. Daphne then gives Fred a kiss, much to his delight. The Demon gives Shaggy and Scooby a smile. Shaggy and Scooby then see Kiss fly away with the diamond. Shaggy asks Scooby if they should tell Velma about what they saw. However Scooby suggests they don’t stating “Why rock her world?”