As they travel through the Intergalactic Cloister, Sonic and the others battle Yellow Zelkova.

Sonic and friends come across a barren planet with 500 Chaos Emerald signals coming from it.

While traveling through space, Dr. Eggman and his forces come across a group of humans battling the armada of Pale Bay Leaf.

Sonic and the others finds a race called Marmolians and head to their home planet.

The Blue Typhoon comes under attack from the Metarex fleet.

The Chaotix trio tries to aide Sonic and his friends as Metarex hunts for them.

The Blue Typhoon arrives at a planet, but Yellow Zelkova attacks the Blue Typhoon.

Shadow invades the Blue Typhoon, trying to kill Cosmo for reasons unknown.

When the team discovers that Cosmo's brain is emitting a signal to the Metarex, they plan on trying to eliminate the signal, except that the signal is connected to the part of her brain that translates sounds and sight. While Tails and Cosmo are torn about this, Knuckles pushes for the surgery.

Sonic and the others chase after Dark Oak to galactic coordinates 0-0-0, where a thousand-year prophecy will bring their plan to fruition.

After Sonic falls into the watery planet, the gang struggles for a way to rescue him and defeat Dark Oak.

The giant seed finally reaches the final stage of its metamorphosis, and Cosmo steps in the battle to stop it.

After the galaxy is saved, Sonic and his friends recalls memorable moments and anticipate their future.