- He decided to win the dog show by dognapping the only three dogs who could beat Big Red.
- Then Big Red was to turn up just before the show and win first prize.

10 seconds sound clip from Scooby-Doo, Where Are You! - Decoy for a Dognapper (S1E5).

You can hear this line at 00:20:36.344 in the Blu-ray version of the episode.

Quote context

[...]

- Why, it's Buck Masters, the owner of Big Red! He's the dognapper!

- You blasted kids! Why didn't you mind your own business?

- Catching dognappers is our business, Mr. Masters.

- After all, Scooby-Doo is a dog, and we love him very much.

- Aww!

- That was quite a plot you kids uncovered. Who would have suspected Masters of dognapping his own pet?

- He decided to win the dog show by dognapping the only three dogs who could beat Big Red.

- Then Big Red was to turn up just before the show and win first prize.

- You said something about a phantom Indian on horseback. What about that?

- Simple. He used a movie projector from the back of his truck.

- Look! Geronimo! He's back again!

- Scooby-Doo! Hee hee hee hee...

- What a nervous night to be walking home from the movies, Scooby-Doo, and all because you had to stay and see Star, Dog Ranger of the North Woods twice.

- Yeah! Yeah! Yeah! Yeah!

[...]