It is sometime in the future, where a certain European city extends far underground, even secret, dark levels that have the key to the past. Ex-assassin Mihai has returned. Sword-wielding Naoto, Haine a mysterious product of genetic engineering and his sometime partner Badou, not to mention the scary but cute twins Luki and Noki, hang around plying their dangerous, and often deadly trades.

Contains an extra story called Dogs: Hardcore Twins in vol. 2.