The Doctor and Nasreen Chaudry go deep underground and find an ancient
society that has been disturbed by the drilling. They are gassed and
taken prisoner just as Amy manages to free herself. The military
commander of the underground reptilians, Restac, is convinced that the
"apes' - their term for humans - are an invading force. Calmer heads
prevail and the Doctor manages to negotiate a truce pending the transfer
of prisoners which he, and some of the more pacifist members of the
reptilians, hopes will lead to a lasting peace. The only problem is that
Alaya, the ...
