In a place known as the Mushroom Kingdom, peace reigned much thanks to the efforts of the brothers Mario and Luigi, and all its inhabitants were happy. However, the Koopa Kingdom swore revenge and tried to dominate the Mushroom Kingdom at all costs, but year after year, the Koopas lost due to Mario, Luigi and their descendants. But, 163 years later, there happened a huge tragedy.

In that time, the Koopa Kingdom managed to dominate the kingdom of the mushrooms, they killed the current Mushroom King and a knight of the kingdom, who were both descendants of Mario and Princess Peach. In addition, the current Koopa King and descendant of Bowser, Exkrower, married the Mushroom Queen, and arrested the newborn princess in the dungeons of the castle. The survivors decided to take refuge away from the koopas and lived isolated from the rest of the world in a small village called Toad Village.

In another place called Mobius, peace was maintained thanks to Sonic the Hedgehog and his friends, and they managed to defeat Dr. Eggman once and for all, but the doctor, considering himself humiliated by the hedgehog, decides to do everything to eliminate Sonic, but he decided to have children in case he did not get his revenge. Over the years, Eggman had two sons, but they lost their father in a accident involving Sonic, and with anger in their heart, Eggman's sons decided to take revenge on Sonic, his friends and his descendants, no matter which could cost.

163 years later, Eggman's descendants eventually succeeded in revenge, through the murder of several blue hedgehogs and Sonic-like hedgehogs. Few could survive, and yet they were being hunted. A female blue hedgehog, fearing for the lives of her two children, handed them over to a friend, but the same friend was surrounded and eventually died. However, both managed to survive, although they are in different places. One child eventually went to Luaenno, a kingdom created by refugees from various cities, and the other child disappered.

More 6 years later, another event occurred in both worlds. A great scientist named Genna Joyce Gaad ended up joining the two worlds through one machine and 100 stars of power. Even the machine exploding after the result, she decided to create a time machine, but all attempts went awry. But the following year, King Exkrower and the current descendant of Eggman, Herald, decided to help Genna in his project, despite the Koopa king and the doctor not knowing each other. But even so, both have a common goal, because knowing that the descendants of their enemies could ruin everything, they decided to "cut the evil by the roots," and that would mean the death of Mario and Sonic.