Robotnik sends Scratch and Grounder into space to pillage the asteroid belt, with Sonic and Tails in pursuit.

Sonic frees a prisoner who has been locked at Robotnik's Fortress for 30 years who wants to find his long lost girlfriend which Robotnik also loves.

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.

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.

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.

Sonic becomes the sheriff of Tranquil Gulch, in hopes of keeping Robotnik's robots from harassing the locals.

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.

In his next time-travel stop, Robotnik plans on erasing Sonic's family tree in order to get the third emerald.

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.

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.

An intergalactic huntress visits Mobius, capturing various citizens and falling in love with Robotnik.

Robotnik's attempt to cause Sonic to age rapidly with his newest device backfires, turning him and Tails, and later himself, into babies.

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.

Robotnik attempts to brainwash MacHopper, a friend of Sonic's into doing his dirty deeds, but an explosion causes his memory to become unstable.

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.

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 creates a robot Sonic suit in order to ruin his reputation.

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.

Tails adopts a squishy creature from another dimension named Goobster, who turns out to be a black hole.

When Scratch and Grounder use Robotnik's latest invention to turn Sonic to stone, Tails attempts to foil the duo to ensure Sonic's safety.

Robotnik pursues Breezie and Robotnik Jr. in order to find out why they betrayed him with the intent of building a perpetually loyal robot wife.

Robotnik seemingly announces his surrender to Sonic, and he invites him to a resort in his gratitude.

Robotnik imprisons a satirical cartoonist for making fun of him in his comic book, much to the chagrin of his biggest fan, Sonic.

During a fair in his honor, Sonic's shoes are stolen and he and Tails use detective intellect to find the thief.

Sonic tries to save a gorilla that is under Robotnik's control, while Coconuts finds the gorilla's lost baby and plots to use it against Sonic.