Fanscription - Scooby-Doo 3 The 13th Ghost

so something I always saw. James Gunn reallly wanted to develop a third scooby-doo script written by James Gunn. his story would've been about The Mystery Inc. gang are hired by a town in Scotland who complain they are being plagued by monsters but we discover throughout the film the monsters are actually the victims. Scooby and Shaggy have to come to terms with their own prejudices and narrow belief systems". Naturally, this revelation left fans puzzled and lamenting the cancellation of the project.

but what if he actually helmed it finishing the live action trilogy
So here's what I decided to do for it.

1: The plot instead would be about The Mystery Inc gang now being relevant they soon discover after it all there's not a lot of masks to uncover. Shaggy has reunited with his girlfriend Maryjane and the two have decided to take their relationship further  Until an old foe is in need of the gangs help with one final mystery to solve. The Awakening of the 13th Ghost.
2: This story would not only see the return of Maryjane (played once again by Isla Fisher) but introduce 2 familiar scooby-doo characters. Vincent Van Ghoul (played this time by Tim Curry) and Colton Rogers (played by Robin Williams) Shaggy's father who finally gets to see what he's up to being roped into the mystery with the gang.

The ending since it would be the last film. Mystery Inc would finally go their seperate ways. Fred and Daphne would go on to train newcomers to spawn various teams. Velma would probably write a novel idk on those parts but the main this would be is that Norville Rogers would not only be with his trusted pal Scooby-Doo but he'd be marrying Maryjane

or what do you guys think let me know?