Chiwa, a resident of the upper world, abandons his place on an elite course to become an officer in the underworld, despite the dreams which warn him to stay away from there. There he encounters his fellow special force members Nanairo and Juuya, who are both superhumans known as "Crows." Crows are humans who have been modified by the crime syndicate "Joker." Crows who escape the syndicate are taken in by the police and become members of the special force whose duty it is to defeat Joker. While sent out to observe the two Crows during one of their missions, Chiwa is saved from danger by a man who appears to know him...?! (Source: The Zero Alliance)