The Midnight Society continue to go in search of the original members who each hold a clue to the mystery. Part three focuses on Vange and Andy's search for 'The Riddle Man'.
| Name | Type | Role | |
|---|---|---|---|
| D.J. MacHale | Writer | ||
| Alexandra Clermont | Guest Star | ||
| Sheena Larkin | Guest Star | ||
| Sydney Freeston | Guest Star | ||
| Tod Fennell | Guest Star | ||
| Anik Matern | Guest Star | ||
| Emily VanCamp | Guest Star | ||
| Philip Spensley | Guest Star | ||
| Walter Massey | Guest Star | ||
| Ross Hull | Guest Star | ||
| Matt Smiley | Guest Star | ||
| Ian Beny Anderson | Guest Star | ||
| Ryan Cooley | Guest Star | ||
| Bill Rowat | Guest Star | ||
| James Bradford | Guest Star | ||
| Anthony Etesonne-Bedard | Guest Star | ||
| Bob McDevitt | Guest Star | ||
| Mark Soulard | Director |