Robotnik buys new gadgets from an enterprising salesman to help Scratch and Grounder catch Sonic, but winds up regretting his purchases when they keep backfiring.
Robotnik fools Captain Rescue into capturing Sonic after the aging superhero lets his guard down, so Tails must convince Rescue to be his old self again in order to save Sonic.
When Sonic saves a female hedgehog named Breezie, he falls in love. Sonic does not know that Breezie is a robot that Dr. Robotnik created to keep Sonic occupied while he floods a village near his fortress.
Grounder accidentally puts a "genius chip" in his head and it makes him so smart that he easily captures Sonic and even takes over Robotnik's operations.
Sonic and Tails infiltrate Robotnik's new Casino Night Zone to stop him and his henchmen from scamming a group of sheep into becoming Robotnik's slaves.
Scratch suffers a blow to the head and believes that he is his favorite television character, Edgar Eagle. Sonic uses this to his advantage in preventing another one of Robotnik's schemes.
On the way to stop a train of explosives from arriving at Robotnik's munition factory, Sonic and Tails must deal with a duo of bears named Big Griz and Mad Mike after Scratch and Grounder tell them that Sonic and Tails are the enemies.
Robotnik's obnoxious mother visits her son on her birthday and expects a present. After he fails to destroy a nearby forest as a present, however, she decides to capture Sonic as her own gift.
Sonic must save a family of sloths from Dr. Robotnik's slow-motion ray. But when he himself is slowed down by Scratch and Grounder, Tails and the sloth family must take action.
Robotnik and a rival named Brandon Quark try to cooperate in capturing Sonic. However, Sonic tricks them into becoming enemies, and they try to outdo each other.
Robotnik's insane cousin, Dr. Warpnik, captures Tails and lures Sonic into his Zone of Confusion in order to enact revenge on Robotnik for banishing him.
Sonic and Tails help an alien prince fix his space shuttle so he can return to his home planet for his coronation before his younger brother is crowned in his place and has Mobius destroyed.
On Sonic's birthday, Tails builds a flying bicycle. Realizing Tails' potential with mechanics, Professor Von Schlemmer invites Tails to be his research assistant.
Robotnik goes time-traveling to find the four Chaos Emeralds that bestow the user unlimited power. His first stop is the time of Blackbeard the Pirate, where he enlists the pirate's help to find the first emerald.
Robotnik's next stop in his time-travel is the Middle Ages, where the second emerald is. Sonic follows him, but Robotnik, with the unwilling help of a local wizard, obtains the emerald and takes over the kingdom.
Despite the intervention of Sonic and Tails, Robotnik obtains the fourth and final emerald in prehistory. With the emeralds gathered together, Robotnik uses them to become an all-powerful being.
A chemical accident caused by Coconuts ends up giving superpowers to Robotnik, who quickly uses them to threaten Mobius's world leaders and publicly humiliate Sonic.
Robotnik threatens to demolish an airport, a lighthouse, and a train station. Sonic is forced to travel to all three places in order to remove the bombs.
Outraged by a popular song about Sonic, Robotnik outlaws music on Mobius and takes the song's composer captive with the intent of creating his own song.
A pickpocket named Easy Eddie picks at Robotnik's Chaos Emerald ring, much to his anger. Sonic must keep Easy Eddie hidden so that he can discard the ring.
Wes Weasley has sold out to Robotnik, and lures Tails, Sonic and all of their friends to a yacht under the guise of a "Hero of the Year" ceremony to thank Sonic.
