"It's one of the hardest and most dangerous trials Sonic has ever faced. The all-powerful Enerjak has returned, and in a matter of minutes reshapes the face of Angel Island in his chaos-fueled fury! Who is hiding behind the golden mask--one of Sonic's oldest friends?! It's all-out war as Shadow the Hedgehog, the Chaotix, Dr. Eggman's Egg Fleet, the Destructix and more pile on in the fray to stop a god and save the world! Knuckles' life hangs in the balance, and not everyone will walk away from this one!"--Summary from amazon.com.