Designer Raymond Cusick recalls his work on The Keys of Marinus, and discusses the challenges that this story held, with its weekly changes of location and inventive set-pieces.
| Actor | Role |
|---|---|
 Raymond CusickHimself | Himself |
 William HartnellThe Doctor (archive footage) | The Doctor (archive footage) |
 William RussellIan Chesterton (archive footage) | Ian Chesterton (archive footage) |
 Jacqueline HillBarbara Wright (archive footage) | Barbara Wright (archive footage) |
 Carole Ann FordSusan Foreman (archive footage) | Susan Foreman (archive footage) |
 George CoulourisArbitan (archive footage) | Arbitan (archive footage) |
| KKatherine SchofieldSabetha (archive footage) | Sabetha (archive footage) |
 Robin PhillipsAltos (archive footage) | Altos (archive footage) |