As shown by the video, the Doctor and Peri arrive on Thoros Beta, the Doctor's curiosity piqued on the availability of advanced weaponry by the Warlords of Thordon. As they explore a cave system, the Doctor discovers Sil, an arms dealer for the Mentors that are supplying the weapons. Exploring further, they find that the scientist Crozier in Sil's employ is attempting to perfect the ability to transplant the brilliant mind of Kiv, Sil's superior, into another body to overcome Kiv's pending death. When discovered, the two make their escape with the warlord King Yrcanos, one of Crozier's test subjects.