It's high time we got to the bottom of these shenanigans.
3 seconds sound clip from Scooby-Doo, Spooky Space Kook (S1E15).
You can hear this line at 00:19:03.231 in the Blu-ray version of the episode.
Quote context
[...]
- We're too late. That ghost has gotten to Shaggy and Scooby first.
- Well, we're glad we found you.
- What are you doing here, Mr. Farmer?
- I got worried about you when I saw your car parked by the gate. That's when I called the sheriff.
- It's high time we got to the bottom of these shenanigans.
- Sheriff, look! He's getting away!
- I think our glowing friend just made a bad mistake. Come on!
- Now take a look at our ghost from outer space.
[...]