Orbot and Cubot must defeat a living computer virus in the cyber world.

After seeing a cross-eyed moose, Sticks is convinced that she and her friends are cursed. They set out to find a mystical marmoset who is the only one who can remove the curse.

When Tails' workshop is destroyed by a fire, Sonic, Knuckles, and Amy each have conflicting versions of how it happened.

After a particularly harsh defeat, Eggman comes to the conclusion that he never wins against Sonic because he is always facing him on favorable ground. So Eggman concocts a plan to have Sonic fight him underwater. Motivational speaker Soar the Eagle will have to use all his coaching talents to help Sonic overcome his phobia of the water in order to defeat Eggman.

During a fight against Eggman, Knuckles suffers amnesia. His friends try to help, reminding him of his worst blunders via flashbacks. But he becomes more depressed when he learns that he is the last of his kind - the final echidna. Feeling all alone in the world, Knuckles sets out to find a foster family among the Villagers who might be willing to take him in.

When the Village's power source, the Meroke Chrystal, stops functioning, the gang must go in search of a replacement. They need to solve a series of puzzles in a trap that was built by the ancients to get it.

Eggman’s nemesis Nominatus is back. With the help of his two virus minions he tries to take over the world… from outside the computer!

Sonic and friends must face their most dangerous foes in order to prevent a disaster that is going to destroy the universe.