The Adventure Begins is an Ash & Friends spoof to the Thomas & Friends special of the same name.
- Ash Ketchum as Thomas (Veronica Taylor)
- Kevin Keene as Edward (Matt Hill)
- Shaggy Rogers as Henry (Matthew Lillard)
- Terry McGinnis as Gordon (Will Friedle)
- Raimundo Pedrosa as James (Tom Kenny)
- Ritchie as Glynn (Tara Jayne)
- Suzy as Annie (Megan Hollingshead)
- Pietra as Clarabel (Carol Jacobanis)
- Dr. Anna as Judy (Megan Hollingshead)
- Dr. Proctor as Jerome (David Brimmer)
- Arcanine as Coaches
- Beedrill as Troublesome Trucks
- Steven Ketchum as Sir Topham Hatt (Dan Green)
- Ellen Ketchum as Dowager Hatt (Carol Jacobanis)
- Mark Morgahan: A long time ago on the land of YTV, there was a big school known as The Cartoon University. The game master working in school was Kevin Keene. He helped to get Beedrill and Arcanine ready for the larger characters. The future Batman in school was Terry McGinnis. He loved to take the big Arcanine out, but he didn't much care for some of his other jobs.