The Doctor talks to Ambril and Chela to try and stop the 500th anniversary celebrations. A possessed Tegan finds herself in Dugdale's Hall of Mirrors to where she summons Lon. The Doctor and Nyssa return to the caves.
Quest roles:
Brian Miller(Dalek Voices (voice)), Colette O'Neil(Tanha), John Carson(Ambril), Martin Clunes(Lon), Jonathon Morris(Chela)