In the final series episode, the Solar Alliance learns that the Feral Empire is planning a galactic war. Meanwhile on the forbidden planet of Lyra, explorers uncover a deposit of uranium, and the Captain and Video Ranger depart for Lyra with an advance plan to mingle in disguise upon arrival. However, they are discovered and captured. The false King Mergo releases the still-disguised Video Ranger, while the Captain discovers a quasi-Elizabethan culture on Lyra. But Duke Philips discovers the Ranger's true identity, and Baron Tilist is ordered to exterminate him. The Captain manages to effect the Ranger's rescue, and to free the genuine Lyran king from his dungeon captivity. Mergo challenges the Captain to a fencing duel, and meanwhile one of Tucker's continuing pranks endangers Captain Video and the Ranger. At this time, Mergo and the genuine King of Lyra come face to face in a showdown, after which Captain Video restores the rightful king to the Lyran throne.
—Louis Rugani