One day in 20XX, the alien pig prince who planned to take a human body as his home arrived on Earth, but unexpectedly discovered that the human being he wanted to live in had not yet been born! The pig prince, who has nowhere to settle down, got to know Saiji and Rubi. The three pulled various funny pranks on humans, causing humans to have baldness, bad breath, headaches, emotional crisis and other problems.

At only 12 years old, Takumi Harada is already hailed as a prodigious baseball pitcher. But when his family moves to the backwater town of Nitta, Takumi has no choice but to join his new school's unskilled baseball team. This development has little effect on the boy, as he believes it is more interesting if this no-name club becomes a powerhouse due to his presence. However, due to his overwhelming talent, Takumi is in need of a catcher able to keep up with his pitches. His worries are soon put to rest after meeting Gou Nagakura. As his fan and fellow student, Gou is eager to prove that he is not a simple braggart, but rather a player skillful enough to catch Takumi's pitches. Amid struggling to form a "battery" with Gou, Takumi comes into conflict with his new teammates due to his irreverent personality but grapples to find the true joy of the sport under his grandfather's guidance.

It is 199X A.D. In Kushiro, Hokkaido, three bodies of Dragonite appear. Possessing overwhelming destructive force, they attack the city. They also awaken the evil Jashin Drago from the holy seal he was trapped in. 200 years ago, Drago was trapped in the seal by a holy warrior with the tattooed mark of the Liger. Assuming that the warrior is dead, Drago and Empress Zara are free to conquer the Earth using their army of biomechanical beasts. Even the Japan Self-Defense Forces are no match for the Dragonites' awesome power. One of the people fleeing is the protagonist, a milquetoast 16 year old boy named Ken Taiga. Unbeknownst to the Dragonites, Ken realizes that he is the descendant of the Liger warrior! In a burst of anger, Ken's Liger birthmark appears, and he rises his palm into the air, shouting the henshin command, "LIGER!!!", which then covers him in demonic long-haired biomechanical armor. Ken transforms into Jushin Liger to fight the evil forces of the Dragonite!