The series takes place during the year 2030, in Choutokyo, Japan. Through the game "Buddyfight", humanity is able to interact with the residents of other worlds: Buddy Monsters. Chosen humans (known as "Buddyfighters") become "Buddies" with Buddy Monsters to play the game. There are those who choose to use the power of Buddy Monsters for evil, but the "Buddy Police" puts a stop to these criminals. Gao Mikado is a student at Aibo Academy, and is a very nice guy, even if he doesn't look like it. His life changes when he meets the son of the hero of the Dragon World: Drum Bunker Dragon (whom he nicknamed 'Drum') that he drew from a pack in class one day.

Gao Mikado has been chosen to fill in for Tasuku Ryuenji while he is away for training. One day, an illegal monster appears looking for the strongest Buddyfighter. After being defeated by Gao, he tries to warn everyone of an upcoming threat, but his memories are stolen by a mysterious person. Just then, 100 illegal monsters appear on Earth, but rather than attacking, they go away leaving everyone worried and confused. Shortly after that a "mysterious" fighter calling himself "Death Shido" starts hunting Tenbu using the Hundred Demons. To combat this threat, the Buddy Police forms the Youth divison and recurits Tetsuya and Zanya. Sometime later a Hundred Demons Hunter appears, and Tasuku returns from his training with a new power. Ikazuchi decides to hunt Tenbu himself and reveals that he's released a very dangerous monster named Yamigedo, who devours Tenbu. To reseal Yamigedo, the eight Omni Lord must be found, Drum becoming one of them after Tenbu's death.

Gao Mikado, a 6th year student of the Aibo Academy Elementary Division, is partnered with Dragon of the Sun, Bal Dragon, a monster born from a mysterious egg. To earn the coveted title as the strongest fighter in the world, Gao and Bal team up to challenge other fighters in the "World Buddy Cup". The two will have to battle others in a card game called Buddyfight, which allows monsters to fight alongside humans as buddies. Their rivals include ex-Buddy Police Tasuku Ryuenji, and the self-proclaimed strongest combination, Gaito Kurouzu and his buddy monster Black Death Dragon, Abygale. Meanwhile, evil-doers are aiming to acquire Bal's special abilities. Kyoya Gaen, and his buddy monster Demonic Demise Dragon, Azi Dahaka are up to no good. Kyoya is already one of Japan's richest icons and is also rumored to be one of the strongest Buddyfighters in the world. What could they possibly be aiming for? And why are they seeking this "Ultimate Dragon Power”? With the passionate shout of an impact call, let the power of the impact monsters be known! Now let's raise the flag!

The ten parallel realms connected to Earth are known as Worlds. At long last, the time to decide the Worlds' Number One has come! Gao Mikado, a sixth-grader from Aibo Academy elementary division, has been chosen to represent Dragon World in the World Buddy Masters tournament. Guided by a messenger who claimed to be Saint Holy Sword Dragon, Gao went to Dragon World itself in search of his new Buddy! As if that was not an adventure enough, Gao interfered with the seal on an ancient shrine and released a forbidden monster! Known as the Demon Lord Dragon, Batzz, this forbidden monster had once devastated the continent of Dragon World. Batzz is a tyrannical monster which pays no heed to anyone. Yet, Gao believes he can become Buddies with even such a monster, and entered the tournament with him. Ten representatives from ten Worlds. One legendary Mirage Card that is bestowed to the winner. An organization plotting for the legendary card, led by a man called Wisdom. What will Gao, and his new buddy, Batzz get themselves into this time!?

The Gao Genuine Gameface Tournament, otherwise known as the GGG Cup, is underway after a lull action after the defeat of Wisdom and his ambitions. Famous fighters and monsters from across the worlds are invited to participate in the many events and, for the special ones, compete in the matches of the tournament.

The anime's story takes place 23 years after the events of Future Card Buddyfight X and centers on Yuga Mikado, son of Gao Mikado. Because Yuga is talented at games, he is known as the "Ace of Gaming." However, Buddyfight is Yuga's first card game. Yuga's Buddy is Gargantua Dragon, who is also known as Garga.