Scooby and the Gang won a prize trip to London to visit a rich british club known as the League of the Unknown, who were long friends with Daphne's parents, but when they see strange things going on, Scooby and the Gang must find out what's going on.
- Scooby-Doo (Frank Welker)
- Shaggy Rogers (Matthew Lillard)
- Fred Jones (Frank Welker)
- Daphne Blake (Grey DeLisle)
- Velma Dinkley (Mindy Cohn)
- The League of The Unknown:
- Moss Nedry (Greg Ellis) - the head of the club, and kisses Daphne on her cheeks, revealing he did that a long time ago to her mother, he has the similarity of Sebastian Shaw
- Juliana Nedy (Kath Soucie) -Moss's wife, she has the similarity of Emma Frost
- Hans Hammerson (Jeff Bennett) - he has the similarity of Harry Leland
- Lord Duke Cobb (Jim Piddock) - he has the similarity of Donald Pierce
- Theresa Valch (Tress McNellie) - she has the similarity of Tessa
- Bruce Milkson (Jim Piddock) - Shaggy finds a card that belonged to the manner of the League of the Unkown!
- Cranston Rottington (Dwight Schultz) - Scooby and Velma finds Red Paint on his hands that were on the windows!
- Pryce Reginald (Robin Atkin Downes) - Fred found out he was a member of the League of Unkown!
- Nina LeBeque (Erin Tropy) - Daphne sees that her Glasses were cracked and were the same size shards found after Mr. Hide left the scene!
- Daphne saw a picture of Ariel the Little Mermaid
- Velma realized that there were nine dials of Ariel, Jesse McCartney, Joyce Meyers, Odette, Mary Jane, Daphne Blake, Velma, Fred and Shaggy
- Lord Cobb (Jim Piddock) - to cheat the family fortune!
- This has nothing to do with Crystal Cove.