In a futuristic city with lost memories, an expert negotiator fights threats to the city with the help of an android and his own giant robot.

Paradigm City, a city of amnesia and a place of belonging. It remains populated by forgotten pasts and the ruins of their labors due to a calamity 40 years ago. Shrouded in a fog-like mystery, it is up to people like Roger Smith to shine a light through the mist. Acting as a professional negotiator and suave agent, Roger is a self-tailored ladies man whose only love is for funeral black. However, as he gets deeply involved with his clients, what often starts as a simple negotiation evolves into Roger saving Paradigm from crime and peril. In the process, Roger stumbles even deeper into the untold folds of the city. As a rule, things are hardly ever as they appear. Serving as gray knight in a gray world, Roger is not without allies. By his side are Norman, a loyal and widely skilled butler, and Dorothy, a human-like android with deadpan snark. Together with the relic Big O, a jet-black mecha of gargantuan size and weight, they help Roger serve iron justice to Paradigm's lurking villains as he discovers the truth about 40 years ago.—MAL Rewrite

Roger Smith acts as a negotiator in a city where everyone has lost their memories and keep it that way. When he isn't helping hostage situations, he's saving the day in a giant robot known as Big O. Although Roger has no idea why the "megadeus" (Big O) responds to his commands or why his butler seems to be a master at fixing the high tech machine, he starts to question the forgotten past after the events started by an unsual case involving an android called R Dorothy. While he and Dorothy begin a Henry Higgins/Eliza Dolittle style of friendship, villains and mysterious characters enter with clues leading up to something that may bring out an emotion Roger has tried to fight all of his known life - fear.—Max Vaughn