Scooby-Doo and Scrappy-Doo

Season 1, Episode 2

Episode Title: The Night Ghoul of Wonderworld

Air Date: 1979-09-29

Overview:

The gang buys Velma her fantasy, which is to be ""Watson for a day"" to a robotic Sherlock Holmes in a futuristic Londonworld at the Wonderworld amusement park. Although it's all supposed to be a game, there really is a crime to be solved.