Roger Smith works Paradigm City as a professional negotiator, one of the few people still willing to operate in a metropolis where every resident lost their memories forty years ago. Backed by android partner R. Dorothy Wayneright and his butler Norman Burg, Roger settles disputes by day and pilots the giant robot Big O when talk fails, digging into the city's buried past one case at a time. Published alongside the television anime, this manga takes the same premise in its own direction.