Dr. Eggman triggers an explosion inside his facility with the last Chaos Emerald, transporting Sonic and friends to a world inhabited by humans.
With the aid of Chris' grandfather Chuck, Sonic must rescue his friends Cream and Cheese, who are being held captive in a military installation.
When Eggman launches an assault using E-23 Missile Wrist, Tails, Chris and Amy try to take it down. But the powerful robot is a formidable foe.
The president sends a spy to Chris' school, posing as a teacher. When a Chaos Emerald is found, both Eggman and Sonic scramble to get it first.
After being duped by Eggman, Knuckles blames Sonic for being trapped in the human world and challenges Sonic to a fight.
Eggman dispatches a robot-teacher to brainwash Chris and his classmates, but the robot doesn't stick to the prescribed curriculum.
Sonic and his friends have kept their existence inside the Thorndyke household a secret, but a visit from Chris’ uncle endangers their cover.
Eggman realizes the military is spying on him and sends his robot E-90 into orbit to destroy all satellites. That means no TV for people on Earth!
Chris and his friends visit a beach resort. Their fun is disrupted when Eggman crashes the party, unleashing robots to build a sea park of his own.
Team Eggman and Team Sonic face each other in a game of baseball. The winner's prize is another Chaos Emerald.
The president tries to capture Sonic using a fake Chaos Emerald, but Rouge takes the bait instead, leading her and Topaz into Eggman's base.
Chris and Tails face off against Eggman after the discovery of a third Chaos Emerald. Rouge and Topaz lead an attack on Eggman's base.
Eggman departs with the Chaos Emerald when Sonic saves Tails and Chris instead. Rouge and Knuckles are trapped in Eggman's base with time running out.
The president hosts a party celebrating Eggman's defeat, with Sonic as the guest of honor. Unfortunately for him, Sonic is nowhere to be seen!
Eggman returns to wreak havoc with a new flying fortress, Egg Fort. Sonic wants to take it down, but he needs the X-Tornado to reach it.
After detecting a Chaos Emerald in the Southern Seas, Sonic and friends embark on a retrieval expedition deep inside an ancient sunken ship.
Treasure hunter Hawk offers to give his new friend Knuckles a hidden Chaos Emerald, but Eggman dispatches E-91 Lady Ninja to steal it.
After crash landing in the wild savanna, Tails and Chris lead a protest against the construction of a dam inside a nature preserve.
Sonic and friends visit an old castle where Chris' mother is filming a movie. When a crew member unleashes the ghosts, things get spooky.
Chris and the gang enjoy a relaxing trip aboard his father's cruise ship -- until Eggman's Egg Fort appears inside a glacier!
Sam Speed challenges Sonic to a showdown with his new racing car. Sonic agrees to participate after the president's aide enlists Eggman's help.
Chris and the gang look for Cheese, who's lost in a Chao colony. Thinking the search party has found another Emerald, Eggman dispatches E-66.
Chris' father unknowingly buys a ring made from a Chaos Emerald. He plans a surprise party for his wife, but the gem attracts Eggman's attention.
Sonic can't stop running, and Eggman's E-88 is responsible. His friends try to stop him with the X-Tornado, but it's not easy.
Knuckles calls a truce with Eggman to find all seven Emeralds and return home. Chris becomes depressed at the thought of his friends leaving.
Eggman tricks Chris and Knuckles into handing over their six Emeralds and takes Chris hostage. To rescue them, Sonic fights an Emerald-powered robot!
Six months after the Mystic Ruins appeared, Sonic and Eggman have both disappeared. But something strange is happening with Big's friend Froggy.
After comparing notes about Chaos, Sonic and Tails embark on a Chaos Emerald recovery mission. Knuckles has visions of an echidna 4,000 years ago.
Knuckles vows to continue searching for the fragments of the Master Emerald. He joins Sonic and Tails on a mission to rescue Amy from the Egg Carrier.
Sonic, Tails and Knuckles infiltrate the Egg Carrier. Chris and Big reunite with Froggy, but Eggman stands in their way.
Tails saves Station Square from Eggman's missile and is hailed as a hero. Gamma frees himself and sets out to liberate other robots and animals.
Wanting the Emeralds for himself, Chaos betrays Eggman. Knuckles and Sonic find themselves transported back into Angel Island's past.
While hacking into GUN's computers, Eggman learns of Project Shadow: a top secret operation to create the Ultimate Life Form, led by his grandfather.
Wanted for robbery, Sonic escapes GUN's custody. A few days later, a black hedgehog steals a Chaos Emerald from a museum.
Sonic turns himself in and is held on Prison Island. Eggman arrives with his own plan, while Chris, Amy and Tails want to break Sonic out.
Shadow transports Chris to Robotnik's space colony. Eggman threatens to destroy the Earth with his Eclipse Cannon if the planet doesn't submit to him.
Knuckles takes on Rouge for control of the Master Emerald. To sabotage the Eclipse Cannon, Tails proposes swapping a Chaos Emerald with a fake.
Seeking revenge, Dr. Robotnik plots to crash ARK into Earth. Those aboard set aside their differences, but can they stop its deadly descent?
A trio of detectives from Sonic's world arrive on Earth searching for Cream. Eggman has a change of heart, offering to repair the Moon.
Eggman's Egg Moon eclipses the sun, covering the world in darkness. He offers a temporary artificial replacement, but Sonic doesn't trust him.
Sonic continues his campaign to disrupt Eggman’s sunlight supply service, and the president sends GUN along with Rouge and Topaz to stop him.
Amy decides to go out with Sam Speed after Sonic stands her up on a date. Meanwhile, Bokkun reactivates the robot Emerl to break Eggman out of jail.
While put to work in jail, Eggman sets up a trap for Sonic and friends by turning a horde of home appliances into lethal robots.
Now free, Eggman resumes his evil plans. Mr. Stewart tails him into the sewer with Chris and others, but they all end up prisoners in Eggman’s lair.
Hoping to lure Eggman out of hiding, the president proposes holding a martial arts tournament with a Chaos Emerald as the grand prize.
Emerl goes berserk after winning the Emerald. Sonic and the others try to stop him, but his ability to mimic his opponents makes for a formidable foe.
Sonic and the gang set sail for the last fragment of a lost continent. When they arrive, they meet Eggman, whose Egg Battleship poses a new threat.
Sonic, Knuckles and Rouge pursue Eggman deep inside a volcano. There they come upon an underground world and the remnants of a lost city.
The president orders Chuck to enact Project Homebound before time stops completely. To save both worlds, Sonic and the others must return home.
Tails and Chuck continue developing a device to send Sonic and the rest back to their world. Defying orders, the military goes after Eggman.
Chris terminates the link between worlds rather than say goodbye to Sonic. If the hedgehog doesn't return to his world, time will stop for everyone.
Back in their own world, Sonic's friends await his return -- even Eggman. Six years later, Chris reflects on the many memories he made with Sonic.