Sonic Rivals

The game starts with Doctor Eggman turning Tails, Amy Rose, Rouge and the Master Emerald into cards with his new device. Sonic and Knuckles arrive at the scene and find out what happened. Knuckles, desperate to save the Master Emerald, tells Sonic that teamwork is out of the question and that he needs to find Eggman first. Sonic grins and says that he likes a good challenge. Meanwhile, Shadow the Hedgehog receives a distress signal from Eggman. Suddenly, a mysterious hedgehog named Silver appears from the future. Silver is then chased by Shadow. When they meet, Silver tells Shadow that he must first find Eggman. After numerous conflicts, it turns out that Dr. Eggman is actually Eggman Nega and that the real Dr. Eggman is trapped in a map before history. After a final battle with Sonic, Knuckles, Shadow and Silver, Nega is defeated, everyone is transformed back to their original form and Silver returns to the future with Eggman Nega trapped in a map.