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...

"Sonic and Dr. Eggman have dueled for over ten years now! In that time Sonic and the Freedom Fighters have enjoyed the safety and comfort of their home, Knothole--once a tiny village and now a sprawling city! But the doctor is about to step up his game. "Eggman Empire" is the story of evil triumphing over good, and the heroes' struggle to fight back. As Dr. Eggman unleashes all of his might against our heroes, will they be able to endure?"--Page 4...

"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."--Amazon

"Sonic and Blaze team up with Tangle the Lemur to work together to fend off another robot invasion, and a villain makes a startling entrance." -- Goodreads.com.

While Sonic's friends Mighty and Ray work to save Sonic from the corrupting energies of the Dark Gaia, the Freedom Fighters continue to battle the E-100 killer robots while they pursue the Chaos Emeralds.

Follow the space adventures of Cosmo and his Martian crew.