As the Doctor's trial continues, evidence is presented showing his most recent adventure, one where he faces an old adversary, Sil. As a scientist conducts his unethical experiments to prolong the life of Sil's boss Kiv, the Doctor's memories of the events begins to return and an unpleasant surprise awaits him.
| Actor | Role |
|---|---|
 Colin BakerThe Doctor | The Doctor |
 Nicola BryantPeri Brown | Peri Brown |
 Michael JaystonThe Valeyard | The Valeyard |
 Lynda BellinghamThe Inquisitor | The Inquisitor |
 Brian BlessedKing Yrcanos | King Yrcanos |
 Nabil ShabanSil | Sil |
 Christopher RyanKiv | Kiv |
 Patrick RyecartCrozier | Crozier |
 Alibe ParsonsMatrona Kani | Matrona Kani |
 Trevor LairdFrax | Frax |
| TThomas BranchThe Lukoser | The Lukoser |
 Gordon WarneckeTuza | Tuza |
| RRichard HenryMentor | Mentor |