After destroying the Millennion syndicate and taking his revenge against the man who killed him, Grave earned his rest. Men like Grave do not get to rest so easily, however, and several years later he is reawakened by Mika Asagi who is again in danger. Even after the Syndicate's dissolution the mysterious mutagenic drug called Seed is still flowing through the streets, and Grave has to stop it the only way he knows how: with his guns.
Beyond the Grave
Grave is a deadman, a reanimated corpse given life through synthetic blood. His condition makes him tough to kill, and his skill with his guns and coffin-shaped rocket launcher make him a deadly opponent. He does not speak, but he protects Mika like an older brother.
Another deadman, Juji is significantly more spirited than Grave. His blindness has done nothing to reduce his skills as a swordsman or a shooter. He joins Grave after the two discover that they're both on the trail of Seed.
Unlike the other two playable characters Billy is not a deadman, but rather a ghost haunting an electric guitar. He attacks with bolts of lighting. Billy is a much more easy-going and upbeat character than the rest of the cast. He joins the team along with his friend Juji.
Each level in OverDose is a straightforward path filled with mooks just itching to get shot. Enemies and scenery give points (called beats) when destroyed, but the number of beats awarded depends on how long the player has been in combat, and will reduce in number if they go too long without shooting something. Defeating enemies also charges up the Demolition Shot, a super powerful weapon that can either fire straight ahead, all around, or slow time. Damage caused by the Demolition Shot also rewards points (called jackpots) which will be graded at the end of a stage. A third type of points, called Artistic Points, are rewarded by playing well, and reaching a high number of Artistic Points will cause Grave and the others to use new moves.
Playable levels are bookended by long, talking-heads style cutscenes.