Episode 1: Destiny
Kentaro Shiratori and Takeshi Kido were born at the same time in the same hospital on the evening of an unusual planetary alignment. Kentaro is intelligent and Takeshi is physically strong, and they have the same romantic interest in their junior high school mate, Yuko. On their birthday, a good spirit, Kopu, appears and tells them that an evil spirit Gomon is about to destroy the world, and they were chosen to battle. Kopu gives them a special radar, Bop, to tell them when Gomon is near. A giant stray dog monster, possessed by Gomon, attacks people in Taiyo City, and Kentaro and Takeshi transform into Barom One to battle.
Episode 2: Out Of Control
Takeshi is happy to have the power of Barom One, but Kentaro does not like to fight, so he hands the Bop to Takeshi to avoid trouble. However, after Kentaro's father, Kenichi trades in his old car for a new car, the old car gets possessed by Gomon and starts attacking Kenichi and other people on the street. Kentaro takes it personal and accepts the responsibility to fight as Barom One to save people. Kentaro and Takeshi transform into Barom one to battle the giant used car monster.
Episode 3: Panic
A monkey named Momo-Taro escapes from a zoo, gets possessed by Gomon and returns to the zoo. When Kentaro, Takeshi and Yuko attend a rock concert at the zoo for its 100 th year anniversary, the Bop reacts to Momo-Taro. To evacuate the crowd safely, Takeshi and Kentaro lie to the crowd that an elephant is running wild, but they get caught. When the band starts playing loud music, Momo-Taro turns into a monster, letting the other wild animals loose, and the crowd panic. But an elephant trainer at the zoo talks to an elephant with his heart and the elephant regains sanity and defends the trainer from the monster. Barom One battles the giant monkey monster.
Episode 4: Wave
Barom One incident at the zoo causes a media frenzy in Japan. Kentaro, Takeshi and Yuko visit a biotech lab for their school assignment and run into some rude kids who damage a Venus's Flytrap. Then, they get killed one by one by a giant flytrap monster. Kentaro starts wondering whether he should save the people who cause harm, too.
Episode 5: Omen
A pet shop is robbed and Hercules beetles, which are worth 500,000 yen (4,000 dollars), are stolen. The Hercules beetles are put up at auction. The beetles get possessed by Gomon, and Barom One saves the robber from the monster. Barom One's glare into the robber's eyes makes the robber feel guilty.
Episode 6: Antagonism
Taiyo City Police Departments requests Kentaro's mother, Mariko, to analyze the monster's DNA. She finds that the cell sizes are random and that they are of alien origin. On the other hand, Kenichi traces the movement of energy in Taiyo City and finds its connection to the monster cases.
Episode 7: Turning Point
Mariko tells Kentaro that the algae from Lake Ryusei and the DNA attached to the monster's body match. Rintaro reports the connection between the monsters and Lake Ryusei to the police.
Episode 8: Surfacing
Yuko tells the press that she was saved by Barom One in the monster attack. As the public finds out more about Barom One, Takeshi and Kentaro start their own investigation on Lake Ryusei. Then, a foreign object comes up on the lake.
Episode 9: Confession
Thieves steal the foreign object from the lab. Kentaro, Takeshi and Yuko visit Kenichi at the hospital. Then Yuko gets kidnapped.
Episode 10: Darkness
The foreign object is recovered from the thieves, and Mariko finds a living creature inside of it. In the meantime, a mysterious earthquake rocks the whole nation of Japan. Media hold Barom One responsible for the disaster.
Episode 11: Conspiracy
Barom One beats Gomon's attempt to make him a bad guy, however Gomon takes Yuko, Noriko and Ms. Hamada hostage!
Episode 12: Counterattack
Takeshi and Kentaro can no longer keep their identity as Barom One secret. Takeshi's father, Rintaro, is locked in by Gomon, and Takeshi and Kentaro transform into Barom One to rescue him!
Episode 13: Future
Barom One jumps into Gomon's trap and loses energy! People run from the collapsing buildings and the world is about to end! Will our planets be saved? Barom One's desperate decisive battle begins!