The TARDIS lands in the Holy Land during the Third Crusade and the crew help save Richard the Lionheart from an ambush, but Barbara is captured and brought before Saladin.

While the Doctor, Ian, and Vicki are drawn into the intrigues of King Richard's court, Barbara has to cope with an impatient Saladin and the vengeful El Akir.

Barbara allies herself with a man whose were murdered by El Akir as the Doctor and Vicki are caught up in Richard's plan to offer his sister's hand in marriage to Saladin's brother.

Ian sets out with a reluctant accomplice to rescue Barbara from El Akir's palace as the Doctor and Vicki try to evade the suspicions of the Earl of Leicester.