The world has completely fallen to the Metal Virus. Sonic the Hedgehog and his friends find themselves on Angel Island, the last safe place, launching a desperate plan with their old foe, Dr. Eggman, to defeat the Deadly Six and reclaim the Chaos Emeralds in a last-ditch effort to save the world.

There's a new kid on the block! And a new... tower? While Tangle tries to initiate the new recruit, Belle, into the Restoration, Sonic, Tails, and Amy investigate a mysterious structure that has popped up. Turns out, it's a maze of twisting corridors and crazy challenges! Can they pass this test with flying colors?

On a recon mission with the new Diamond Cutters--Tangle, Whisper, and Lanolin--Sonic discovers that the Eggperial City is harnessing the resources around it to grow ever larger. The Diamond Cutters are still getting the hang of working together which leads to trouble when they get trapped. Alone against an army of badniks and a self-replicating city, Sonic calls for back-up and gets more than he bargained for: Tails, Amy, Blaze, and Silver all answer...

After assembling a squad of bad guys, kidnapping Belle, starting a forest fire, and causing chaos in Central City, Starline is finally ready to unleash his monstrous imposters: Surge and Kit! Will his meticulous planning be enough to defeat Sonic and Dr. Eggman? And, in the wake of the climactic battle, both the heroes and bad guys need some time to heal and regroup… except Dr. Eggman, of course, who is always ready to destroy that darn hedgehog....

Surge is angry and plots her comeback, but she needs more power, and she needs it now. Sonic’s friends race to stop her rampage, but there’s something different about her. As things start to look dire for Sonic and Tails, they find support in the form of Surge's old sidekick, Kit! He's on their side...right? But Surge’s plan is bigger than anyone thought! With a little help, she's going to turn the place of her greatest torment into the place...

Following their last battle, Dr. Eggman's been mysteriously absent from Sonic's life. What shocking secret will Sonic discover when he learns the bad doctor's whereabouts? Plus, Sonic isn't the only one looking for Eggman--so's his old frenemy Shadow the Hedgehog! There are twists and turns in the course of this high-speed, action-packed mystery-adventure! But with a little help from his friends--including a new ally--Sonic's fast enough to overcome...

The thuggish twosome, Rough and Tumble, are back and they're looking for vengeance against Sonic and his friends. And they're not the only ones... some of Sonic's greatest foes have returned and, with the help of some new evil allies, have created a threat that's guaranteed to take over the world. Even Sonic can't outrun a Virus for too long.