A traveling magician by the name of the Amazing Lazardo made slaves from the people of a big western city. The magician has convinced them he is able to create earthquakes at will. Alerted of this mysterious magician, the Star Sheriffs begin their investigation.
Fogarty, a human expert in explosives is approached by an undercover Outrider agents sent by Nemesis to plant a bomb at the setting of the upcoming peace summit conference. Fogarty is betrayed by the Outriders who make an attempt on his life but fortunately the Star Sheriffs interfere on time. Fogarty wakes up in the hospital with amnesia.
A female pilot named Mandarin has a huge crush on Fireball. Without knowing why, April doesn't trust Mandarin and doesn't let Fireball out of her sight. Mandarin helps the Star Sheriffs to approach the Outrider's ship where Commander Eagle is being held captive. However Commander Eagle manages to escape and wanders around until he meets an old monk who gives him shelter.
Commander Eagle learns from the old monk that the human race and the Outriders' aren't that different after all. Meanwhile Cavalry Command prepares to send a rescue mission for Commander Eagle, but an Outrider agent infiltrates their base and takes the place of a Cavalry Commander Ghoul. He tries to distract the Star Sheriffs' attention, and has his own plans.
The rescued Commander Eagle resumes his functions and shares everything he has learned during his captivity, as well as the time he was with the old monk. Commander Eagle being a man of his word is trying to keep the promise he made to the monk by reaching peace between the humans and the Outriders. Jesse Blue arrives on planet Yuma as an ambassador, send by Nemesis to negotiate the conditions for the peace treaty.
Saber Rider, April, Colt and Fireball are suspended permanently from duty. Ramrod has been destroyed and the former Star Sheriffs scatter and return to ordinary life. April and Fireball get closer and closer, Saber Rider goes back to his parents and Colt is reunited with Robin. Meanwhile the peace treaty has been broken by the Outriders. Nemesis uses his latest weapon, the Cobalt Blue Blaster to destroy planet Alamo's moon. The Star Sheriffs are reinstated and they are off on board Ramrod II.
Jesse Blue gives 24 hours to Cavalry Command to surrender. Otherwise he will use his Cobalt Blue Blaster once more. Commander Eagle's Cavalry fleet attacks and surrounds Nemesis' base on planet Yuma while he is still inside. Nemesis orders Jesse to send a rescue mission on planet Yuma to save him, but Jesse declines. Soon, Jesse discovers that even though still on planet Yuma, Nemesis still has full control over the Nth Degree.
The Star Sheriffs jump into the Outrider dimension. They are there to plant explosives on the Outriders' planet. Meanwhile Nemesis is finally revealed as a synthetic cyborg with full control over the Nth degree.
To end the war, Star Sheriffs must stop the computer that's still running the Outriders' orbital station and is about to launch a desperate final attack that will destroy Yuma. However, traitorous Jesse wants the station for himself.