Noticing the place to be awfully familiar, Modern Sonic and Modern Tails see Casino Night and Mushroom Hill in the distance. After running through the area, it is restored, and Modern Tails, who had been turned into a statue, is restored as well. After looking around, he finds Green Hill in a white and lifeless state. Suddenly however, rumbling occurs and a Time Hole appears, sucking Modern Tails into it. However, Sonic arrives early, surprising Tails, who asks him to wait.
Meanwhile, in the present, Modern Tails is preparing a surprise party to celebrate Modern Sonic's birthday. The Time Eater attacking Modern Sonic and Tails. A Time Hole then appears and the screen fades to white.
However, he stops after hearing some rumbling noises. The game opens with the distant past Classic Sonic is running through Green Hill. Spoiler warning: Plot, ending details or any kind of information follow.
