The TARDIS lands inside an Aztec tomb belonging to Yatexa in 1430. After the Doctor and his companions leave the tomb, the door closes and locks, leaving the TARDIS inside. Barbara is declared to be Yetaxa reincarnated, Ian is made the chief of their warriors, Susan is made a handmaiden, and the Doctor flirts with an elderly Aztec lady. The Aztecs turn on them when Barbara talks out against sacrifices. The Doctor discovers how to get back into the tomb and they leave in the TARDIS.