The TARDIS arrived on Earth in 1289 where they meet Marco Polo who is in the service of Kublai Kahn. Marco Polo forces the four time travellers to joins his caravan and takes the TARDIS to present to Kublai Kahn. On the journey, Tegana, who also wishes the TARDIS for himself, attempts to kill them by draining all of their water. Surviving on the condensation from the TARDIS, they arrive in Peking were the Doctor plays backgammon with Kublai Kahn. After winning some fortunes, the Doctor ends up losing the TARDIS. He regains the TRADIS when he reveals Tegana for who he is and in the process saves Kublai Kahn's life.