POLO [OC]: Success. My plan has worked. The strangers and their unusual caravan accompany me to Lop. Our route takes us across the Roof of the World, down to the Kashgar Valley and southeast to Tarkand. Here we join the Old Silk Road, along which the commerce and culture of a thousand years has travelled to and from Cathay. I wonder what the strangers' reaction will be when I tell them what I propose to do?

VIZIER: Kowtow. Kneel upon the ground and touch your forehead upon the floor three times.

DOCTOR: (Outraged.) I shall do no such thing!

VIZIER: Kublai Khan is the mightiest man the world has ever seen. Not to pay him homage will cost you your head.

DOCTOR: Well, if it breaks my back, then he can take all of me! So why waste time on small items?