With the peace talks between the Speleans and the Caligars having broken down, King Randor, Prince Adam, and Man-At-Arms journey to Subternia to help them reach a settlement. At the same time, the Evil Warriors decide to attack Castle Grayskull form below as all of their other methods have thus far failed. It is not long before the two groups meet in the depths of Eternia...

On Orkas Island, Dekker, the former teacher of Man-At-Arms, is looking forward to a visit from his former pupil. News of the meeting does not go unheard and Dekker is captured by members of Clawful's species. Arriving on the island, Man-At-Arms, Teela, and Prince Adam begin to suspect that there is something wrong when Dekker does not meet them and they see signs of a struggle...

The newly formed Eternian Council arrives at the Royal Palace for their inaugural meeting. Skeletor realizes that this council can dramatically alter the balance of powr on Eternia and, on the advice of Beast Mat, launches a Serpintaur attack against them. When the masters see dragons flying overhead and lean that even more Sepintaurs are being rounded up at Snake Mountain, they enlist the aid of the Dragon Walkers to form a dragon army of their own...

The Masters are called to Spelea, where they discover Lord Dactys and his warriors defending themselves from a Caligar attack. While King Randor mediates a truce between Lord Dactys and Ceratus, the Snake Men take advantage of the distraction to enter the Temple of Serpos, intent on awakening the Guardians of Old...