As Ventus was traveling between worlds to find Terra, he ends up getting attacked by a mysterious Unversed. He manages to fight it off, however the Unversed flies off towards the Grand Councilwoman's spaceship.
Ventus chases after the Unversed and pursues it throughout the ship. Ventus eventually come across Experiment 626 (Stitch,) along the way, and 626 wanted to help. Eventually both Ventus and Experiment 626 managed to catch up to the Unversed known as the Metamorphosis in the engine room.
The Metamorphosis was spotted causing large amounts of damage to the engine. Ventus and Experiment 626 team up to stop the Unvered from causing more harm to the ship. After a long battle Ventus and Experiment 626 managed to destroy Metamorphosis.