While Sonic had an adventure in Mania, Knuckles and the Chaotix team faced Eggman and the power of the Chaos Rings. Thanks to these rings, the creature can gain great power. Even if this creature is robot... Metal Sonic Kai was destroyed by Knuckles by the Chaotix team before Sonic and Tails got to the Techno Tower. But, after the destruction of Metal Sonic Kai, the power of the Chaos Rings was released and created a large explosion that completely destroyed the Techno Tower. This explosion caused Sonic and the others to scatter across the island. But Eggman is still here, and he is preparing a new weapon to create his own rules in this world and destroy Sonic and his friends. After all, there are other places on this island where Eggman can hide his new deadliest weapons... Be careful, Sonic!