In a dimension where boundaries blur, Sonic, Tails, Knuckles, Amy, and their allies battle the devious Dr. Eggman, who has fused the seven Chaos Emeralds into a powerful machine. As Sonic speeds in, Tails provides aerial support, Knuckles prepares to fight, and Amy fends off Eggman's minions with her Piko Piko Hammer.

Just as they gain the upper hand, Sonic lands a critical hit on Eggman’s machine, prompting the villain to flee. The device malfunctions, creating chaos and opening a swirling vortex that pulls them in. Despite their efforts to hold on to one another, they're sucked into the vortex, leaving Sonic in darkness.

When they wake up, they find themselves in a lush, unfamiliar landscape, realizing they've been transported 120 years into the past.