Synopsis:On an expedition in the Starship Eternia, He-Man, Sagitar, Hydron and Icarus accompanies, Gepple who is investigating the Solar Flares, that are the cause of the continued interruption of communication that they have been experiencing for some time. Gleep wonders why he was brought on the expedition and Gepple tells him that he needs a robot to help him in the expedition. Sagitar experiences pain in his head and is told by Hydron to go and get some rest. On his way back to the sleeping quarters, Sagitar has a vision of the annual Horse Lord “Running Of The Herd”. When he comes to, he realizes that he miscalculated the dates and what he was experiencing was the "Call Of The herd". Sagitar goes crazy and insists that they change course. After shouting out outrageous accusations, Sagitar begins to brawl with Icarus and Hydron, forcing Gepple to order Gleep to use his Stun Ray. Before Gleep could fire the Stun Ray, He-Man enters the room and wrestles Sagitar to the ground, calming him. After a few moments, Sagitar tells them that he has received the call for the “Running Of The Herd”. The “Running Of The Herd” is his home planet, Equinox, most important ritual. Sagitar explains that many years ago, the Horse Lords were once horses, who ran free through Equinox. As time went on, the horses eventually evolved into Horse Lords. The “Running Of The Herd” is a tradition that celebrates their heritage. If a Horse Lord does not return to Equinox for the tradition, they will parish. Immediately, Hydron and Icarus change course and head to Equinox. Meanwhile on the Moon Of Nordor, Flogg and Skeletor congratulate Staghorn for the information that his spy brought them, about the “Running Of The Herd”. Flogg orders Mutant Troopers riding Terrorclaws to board the Mothership. Flogg plans to be present when the Galactic Guardians arrive on Equinox. On the Planet of Equinox, Baskeeta discusses to General Nekor, as to why Sagitar has not come, but is interrupted by a distress call from Captain Wilkins, warning that they are under attack. The Mutant Mothership has deployed a full-scale invasion on the Horse Lord's Air Field. Eventually, the Mutant Army takes over the Horse Lords. Skeletor and Flogg confront General Nekor and Baskeeta, telling them that they are after Sagitar, and they plan to be the welcoming party. Flogg threatens to destroy the entire planet if they notify the Galactic Warriors. When they arrive, they are greeted by General Nekor and Beskeeta, who immediately seperate Sagitar from the Galactic Guardians by putting them in separate Hover Cars. Beskeeta tells Flogg that he must allow Sagitar to fulfill his “Running Of The Herd”, before the Mutants attack. Flogg angerly agrees. When Beskeeka leaves, Flogg orders his troops to attack during the “Running Of The Herd”. That night Baskeeka travels to General Nekor's house, where thr Galactic Guardians are spending the night, warns them, that the Mutants have taken over the planet and is preparing to attack them. Staghorn warns Flogg that Baskeeta has informed the Mutants of their plan and Flogg tells Slush Head, who has surrounded General Nekor's house, to wait for he and Skeletor arrive, before they attack. Slush Head misunderstands and attacks right away. Slush Head's attack proves unsuccessful. When Flogg arrives, he launches another attack. Using the crystalline fuel from a damaged Terrorclaw, He-Man causes a large explosion destroying much of Flogg's army. Lead by Captain Wilkin and Sagitar, the Horse Lord Army attack pushing Flogg's remaining forces back. Sagitar and Staghorn have a one-on-one battle, which ends up at a cliff side, where Sagitar throws Staghorn into the water below. Staghorn survives to fight another day. The next morning, on the Plain Of Oats, Sagitar and Beskeeta, join in with the “Running Of The Herd”.