The setting is between Gradius III and Gradius IV.

During the " Third Bacterian War ", the planet Gradius defeated the Bacterians, and peace returned to Gradius. After two hundred years passed, Gradius prospered, but when the disappearance of a science vessel which went to a nebula known as "The Evil Range", the colony planets of Gradius were attacked by some unknown force that destroyed 99% of the Gradius Army. The Gradius Army Headquarters decided to launch a desperation attack on the "Dark Nebula", which was the source of the invaders. Four Hyper Space Fighters launched from the mothership with orders to stop them.

The setting is between Gradius III and Gradius IV.

During the " Third Bacterian War ", the planet Gradius defeated the Bacterians, and peace returned to Gradius. After two hundred years passed, Gradius prospered, but when the disappearance of a science vessel which went to a nebula known as "The Evil Range", the colony planets of Gradius were attacked by some unknown force that destroyed 99% of the Gradius Army. The Gradius Army Headquarters decided to launch a desperation attack on the "Dark Nebula", which was the source of the invaders. Four Hyper Space Fighters launched from the mothership with orders to stop them.