3 Years ago, unusual cards rained down on Earth through a dimensional hole. The children collected them and found out that each card contained a giant, hungry for battle monster. Children instantly came up with a strategy game. Back then, monster only acquired its real height and abilities during the game. The cards contained abilities and bonuses for monsters, which were necessary in battle to increase the special power of G. People called this game "Bakugan".

But since then, things have changed.

The story takes place in a 2017, America, New York city.

Bakugan (race) - In their natural form, bakugan are huge creatures like humans, animals, or mythical creatures. Their color and external attributes depend on the attribute and purpose (for example, non-combat bakugans have rounded features and no attacking features). Bakugan can also be in the form of a sphere, while maintaining common external characteristics. Sphere form can easily defy laws of gravity and fly or walk without any trouble. Bakugans are divided into six attribute with unique coloring and playstyles:

attribute are giving bakugans unique coloring and playstyle:

• Pyrus - Fire - red, orange, white and yellow colors with green eyes. For Pyrus Bakugan, the main point of them is to simply overpower through sheer force and shutting down ways your opponent can fight back like gate card bonuses or Ability Cards. Due to this, nullifying cards are very useful to stop your opponent from fighting back with ability cards or Gate effects and Stand Off also gives a great Pyrus Bonus. Average G power of Pyrus bakugans are 1300G - 1700G.

• Aquos - Water - blue, light blue, dark blue, green and black colors with red eyes. Aquos Bakugan usually have average G-Power but use trickery to either boost them or dwindle their opponent to win. Many cards make the opponent feel safe and secure but then cards with powerful effects come up and shock the opponent. Aquos strategy often requires to roll a low power Bakugan on to an opponent's Gate Card to make the opponent think they have the upper hand before you bring down a big Ability Card. Average G power of Aquos bakugans are 900G - 1500G.

• Haos - Light - white, yellow, with light blue eyes. Haos Bakugan have the lowest G-Powers, but strategy and manipulation is the main idea. Haos Bakugan are often in the battle for aid, or switch. They often use abilities such as G-Power Swap and are often credited with winning the battle with the lowest G-Power. Haos Bakugan use very strong Ability Cards. Average G power of Haos bakugans are 1100G - 1700G.

• Darkus - Darkness - black, purple, red, grey, with yellow or red eyes. Darkus Bakugan have a large variety of G-Powers and Ability Cards so there are many ways to use them. Darkus strategy's main gimmic is ability to cancel opponent's ability and gate cards, often shifting the game in their favor. Average G power of Darkus bakugans are 1500G -2000G.

Subterra - Earth - brown, light brown, green, yellow, with red or yellow eyes. Subterra-attibuted often have high G-Power. Subterra bakugans' often stand their ground no matter what, playing off of their own gate cards and ability cards that often cancel or counter opponents' abilities. Average G power of Subterra bakugans are 1400G - 1900G.

• Ventus - Wind - green, light green, yellow, light yellow with yellow or red eyes. Ventus-attributed Bakugan have average G-Power. Ventus attributed Bakugan draw their power from the cunning tactics. They think before they play. They choose their Ability Cards wisely, as the biggest boost is not always the best. They lure their opponent in by giving them the upper hand and just when their opponent is getting cocky, Ventus brawlers spring their trap and come out victorious. Average G power of Ventus bakugans are 1300G - 1800G.

Play field: There are giant arenas for bakugan fighting that are built around entire world, although because of Vestroia energy filling Earth's core, bakugans can transform in their true forms from spheres and fight at any given time.

Gate cards: Gate Cards are cards designed to be placed Arena specifically, although it is also possible to use them out of arenas. Gate cards are divided by type into cards of attributes. Gate cards are highlighted in the color of their attribute. When a player throws a regular gate card onto the field, it increases in size, becomes invisible and becomes a fight zone. There are 3 rounds on each side.

After the card is thrown, the players are playing turn-by-turn. During their first turn, players ALWAYS throw in their bakugans in the fight. After bakugan are thrown into the fight, during their turn a player can choose to throw a bakugan onto the gate card, or activate ability card.

Once play field is set, a life gauge appears.

Combat rules: Usually only bakugan is used by player, although it is possible to use multiple bakugans in same fight. Bakugan with the higher G-force wins. While bakugans are fighting each other the outcome of the fight can be changed by using ability cards or opening a gate card. Both players can use up to 10 ability cards before battle ends. When one bakugan wins, the life gauge of a player is going down by the difference in bakugans' Gs. 10% - 100G. 50% - 500G. 100 / instant win - 1000G. Once one of brawlers lost, players throw in new gate card and their bakugans back into battle. The fight goes on until one of brawlers' life gauge reaches zero.

Ability cards: To activate the ability card, a player must throw a card onto the field or just hold it in their hand. During activation, the ability shines with the color of its attribute, and then disappears. Ability cards can be connected to one of the six attribute or to the bakugan that was thrown onto the battlefield.

Mechtogans: Mechtogan first appeared as an entity that wreaks havoc. Despite their mechanical nature, they are fully sentient beings. Bakugan has to tame their Mechtogan in order to control them. Mechtogan sometimes closely resemble the appearance of the Bakugan that spawned them.

In order to control a Mechtogan, a brawler and Bakugan must be in sync with each other, only then will the Mechtogan will be able to communicate with them and fight at their leisure. Mechtogan is spawned when the abilities of both the brawler and their Bakugan has their power go to the highest level and take a physical form from it. Then, if their hearts are not linked to each other, the balance will become unstable and the Mechtogan will go out of control. Mechtogans G-power: 3000G.