While trying to retrieve the 7th Chaos Emerald from Dr. Eggman, Sonic and Friends are transported to the human world where Sonic is rescued by a boy named Chris.

When Sonic discovers that Cream and Cheese are being held captive by the military, Sonic, with the help of Chris' grandfather Chuck, finds and frees them only to be caught in a trap until Tails come to the rescue

When Eggman tries to use E-23 to take over the world Amy, Knuckles and Tails launch an unsuccessful counterattack, until Sonic arrives, and with a ring from Tails, destroys E-23 and saves Amy with the help of Knuckles

Chris' teacher is replaced with the President's spy, and the first Chaos Emerald appears at a construction site. It's then a race to the stone between Eggman and Sonic, with Chris stealing it from

After Eggman tricks Knuckles into blaming Sonic for being stuck in the human world, Knuckles challenges Sonic to a duel allowing Eggman to capture Chris, Amy and Tails using E-47, until Knuckles

Eggman tries to use his robot to brainwash Chris' class but when Intellihente winds up teaching more than brainwashing, Eggman steps in to put the children in permanent detention until a worried

When Mr. Stewart drops by for a surprise visit, Chris and Chuck are able to keep Sonic and Friends' stay a secret but after the S-Team Leader, Chris' uncle, arrives things get messier and everyone including Ella and Mr. Tanaka find out Chris' secret

After Eggman discovers that he is being watched by the military he sends E-90 to swallow the satellite, but this disrupts all television so Chuck and Tails turn Tornado into Tornado X allowing Sonic to enter and destroy E-90.

After Chris, Amy, Cream and Cheese arrive at a resort, Eggman appears and tries to take over but Sonic arrives and tries to stop him only to be saved by Amy from E-39.

It's Team Sonic vs Team Eggman in a baseball game for a Chaos Emerald, Team Sonic falls behind at first but then wins with a Sonic super-play, only to have Eggman steal the Emerald in the end.

The President plants a fake emerald to try and attract Sonic but Rouge takes the bait instead and winds up searching Eggman's base, with Topaz, for a Chaos Emerald, until she encounters E-70 and

Tails and Chris discover the third Chaos Emerald in a field and fly for it in the X-Tornado but Eggman and E-51 catch up and trap them, meanwhile Rouge and Topaz launch an attack on Eggman's base.

Sonic saves Tails and Chris from E-51 while Eggman makes off with the Chaos Emerald, at Eggman's base Knuckles appears and helps Rouge plant explosives but they end up trapped.

When Sonic ignores the President's party to take Helen, a wheelchair-bound girl, to pick a flower, the President's aide responds by sending a unit to capture Sonic but Sonic outruns them all giving Helen the thrill of her life and ending up at the party

Eggman reveals his new secret base, the Egg Fort, and attacks Station Square but Sonic hops in the X-Tornado and forces the Egg Fort out into the ocean where he sinks it into the water

Sonic and Friends retrieve the fourth Emerald from a sunken ship, Eggman returns with his Egg Fort and attacks but Sonic uses a ring from Tails to destroy the robot with a Spin Attack

After Hawk shows Knuckles the fifth Chaos Emerald Eggman's E-91 kidnaps Hawk for ransom, but during the trade Rouge enters and Chaos Emerald-keep away ensues until Knuckles defeats the robot, gets

When Sonic, Tails, Chris and the Egg Fort crash land on the Nature Continent after a fight, Tails and Chris protest against a dam while Sonic is caught in a battle against Decoe, Bocoe, E-65 and Eggman, until Tails arrives with a ring

Sonic begins his adventures in a new world.

Sonic and Co. are on a cruise when the Egg Fort appears inside a glacier. Sonic is unable to defeat three E-28 robots, until Knuckles arrives and together they smash the bots and the glacier, but the new Egg Fort 2 emerges from the ice and flies away