The 25 Years of Sonic the Hedgehog

Sonic Unleashed (2008)

At the beginning of the story, Sonic was confronting his nemesis, Dr. Eggman, on Eggman's flagship. Eggman then activated the ships defense systems, activating the cannons and bringing forth a horde of Egg Fighters. After seeing the obstacles, Sonic boosted forward and began dodging the batteries fired from the cannons. bounding across the flagship, Eggman brought forth his Mech and unleashed a flurry of machine gun fire. After running across the ceiling while dodging missiles, Sonic ran through the Flagship's hallway. Eggman fired his Mech's grappling hook-like arm and grabbed Sonic. After being pulled to Eggman in the Mech's grasp, Sonic summoned the chaos emeralds from within himself and became Super Sonic in order to stop him, destroying Eggman's mech, Eggman fled in his Egg Mobile and fled from his Flagship. After chasing Eggman through space and destroying half of his fleet, they finally arrived at Eggman's Research Facility and knocking Eggman himself to the ground. As a trap, Eggman pretended to plead for mercy. When Sonic was close enough, he activated the Chaos Energy Cannon, which trapped Sonic in the center and began drawing the chaos energy out of Sonic and the emeralds in a fashion that was clearly extremely painful for him.

After the weapon was charged, Eggman fired a laser at the Earth to wake a monster known as Dark Gaia, splitting the planet. The dark energy of the emeralds was brought out by the ray, transforming Sonic into a monstrous version of himself, and rendering the chaos emeralds gray and powerless. Eggman then opened an airlock which sucked Sonic and the drained emeralds out into space and down to Earth. While Sonic was saved from a fatal landing due to an unknown energy source, he still ended up taking a heavy fall. After pulling himself out of the dirt, Sonic encountered a flying dog-like creature. Sonic then asked the creature what his name was, but the creature couldn't remember his own name or history (which Sonic thought he landed on him, causing the memory loss). Sonic agreed to help Chip restore his memory during their journey.

After exploring the city of Apotos, Sonic named the creature Chip and the two ran into Tails at night. Tails immediately recognized Sonic even though he is in his Werehog form and revealed that Professor Pickle of Spagonia University may be able to help them on their adventure. Once they reached Spagonia, they discovered Dr. Eggman had kidnapped Professor Pickle for his knowledge on Dark Gaia. After traveling to Mazuri and freeing him, Professor Pickle explained the nature of Dark Gaia and revealed that restoring power to the chaos emeralds via the Gaia Temples would help the planet return to normal. Sonic then set out to the seven Gaia Temples to restore the emeralds and reassemble the planet. In Spagonia, Sonic and Chip run into Amy at night, who didn't recognize Sonic in his Werehog form. He later saved Amy from Dark Gaia's influence and she, upon learning her savior's identity, decided to help Sonic and Professor Pickle. All the while, Dr. Eggman made plans to reassemble Dark Gaia and finish Eggmanland.

During the restoration of the sixth chaos emerald and continent, it's revealed that Chip was in fact Light Gaia, the opposite of Dark Gaia, and he lost his memories because, like Dark Gaia, he was prematurely awakened by Eggman's laser when Eggman started the Time of Awakening, where Chip and Dark Gaia was meant to awaken, too early; likewise, Dark Gaia had not yet been fully reborn due to his premature awakening, and Sonic must stop Eggman before Dark Gaia's full powers return to its normal state.

At this point, Sonic traveled to the location of the last temple, over which Eggman had built Eggmanland using an extraction of Dark Gaia's power. While Sonic was able to restore the last emerald and defeat Eggman's newest mech, Dark Gaia became complete, by draining the dark energy that Sonic had that turned him into Werehog, knocking Dr. Eggman out of the way to keep the power for itself. Sonic was too weak to move so Chip used the Gaia Temples to form a body called Gaia Colossus to combat Dark Gaia with, Sonic recovered on the Gaia Colossus and helped Chip fight Dark Gaia. Chip and Sonic hold off the beast, but Dark Gaia managed to drown the planet in darkness, achieving its fully-matured form in the process. Sonic then transformed into Super Sonic using the seven chaos emeralds and took Perfect Dark Gaia down with the help of Gaia Colossus, but the battle left him too drained of his energy to escape. As the final continent moved back into place, Chip flung Sonic back onto the surface while he remained behind. After Sonic woke up, Chip's necklace and some parting words were found on the ground. Sonic then picked it up, and puts on the necklace as a bracelet to remind them of their adventures together. The game ends as Sonic runs off with Tails, who was in the Tornado, to another adventure.