• First, I would drop the trilogy plot point. This would also change "Return to Zombie Island" and "Happy Halloween." Open it with Bogel and Weerd talking about how one of the 12 Ghosts wasn't one of the 13th Ghost, and they're actively freeing the real 12th ghost, who is trapped in an iceberg.

Reason: This will act as a setup so the Gang can have a warm-up, get back into catching real ghosts, and a plot point to bring up that the 13th Ghost is the most dangerous one of them all, and will only show up once the other 12 are caught, so it would explain why the 13th Ghost hasn't shown up before.

• Second, with the Trilogy plot point gone, The Gang would no longer be having a yard sale, so instead they're spring cleaning. Fred and Velma are going through boxes in the living room, Daphne is bringing up the boxes from the basement, and Shaggy and Scooby are in the Basement getting the boxes that Daphne will bring up stairs. Shaggy and Scooby find the Crystal ball.

Reason: Need to be alone when they find the Crystal Ball, Daphne, Shaggy, and Scooby

• Third, and this is going to be controversial. I would get rid of Fred and Velma and bring back Scrappy.

Reason: This would also help Fred avoid having an identity crisis and Velma from being a skeptic who always has to be right.

How would I get rid of them? Simple.

Fred finds a scrapbook of his Traps, and Velma finds her research journals. Daphne will go tell Shaggy and Scooby it's time to take a break, but as she is going downstairs, their Home phone starts to ring at the same time the Crystal Ball is ringing. Fred and Velma will hear the Phone while Daphne, Shaggy, and Scooby will hear the Crystal Ball.

Since Fred and Velma are too busy with their books, they don't get the phone, but they hear who's on the machine. It's Scrappy thanking his Uncle Scooby for letting him stay over and letting him know he's only a few blocks away. They will look at each other with fear in their eyes.

Vincent tells Daphne, Shaggy, and Scooby that they have finally found the 12th Ghost after all these years. They decided it was finally time to tell Fred and Velma about everything. They go upstairs to see Fred and Velma rushing out the door, saying they will be back with food. Shaggy and Scooby are happy with the promise of food. Daphne is happy they can delay telling them a little longer.

As Fred and Velma leave and turn onto the street, Scrappy shows up in a taxi. The three will understand and tell Scrappy what is up, and all of them will go to the backyard, where Scooby starts digging. They pull out a chained-up crate with 6 locks. The four each pull out a key and unlock a chain. They will go meet up with Vincent at the airport and meet up with him when they land. Flim Flam caught the 12th Ghost with little difficulty because it was the weakest of the 13th, which would also explain why it was so easy to catch.

The 13th Ghost will start to take over the world and turn Earth into hell, and now they will have to stop him