Roger and Dorothy battle against three foreign mechs when he takes a hit. Suddenly he finds himself 40 years in the past and living a different life, causing him to question his existence.

Kelly Fitzgerald hires Roger to protect her husband from an assassin. Rumors are the city Senate is killing anyone with knowledge of the past, so Roger and Dorothy begin their investigation.

A strange object from the sky crashes into the city before it is recovered by the Paradigm organization. Roger is tasked with ascertaining the nature of the strange object.

Schwarzwald threatens that he had discovered a powerful mech called the Leviathan. Roger scrambles to find him before he unleashes its power on the world.

Beck once again busts out of jail and captures Roger as part of a scheme. Copying Roger's face and voice, he commands the Big O to go on a rampage.

A serial killer is going around killing androids, prompting the government to put a new inspector on board. Roger begins his own investigation and runs into Angel.

Roger tries to understand his flashbacks.

The Big O battles the Bonaparte when Roger realizes that Dorothy is in danger. He leaves the Big O to fend for itself as Angel confronts Alan, who is holding Dorothy hostage.

The military police starts capturing anyone accused of being an Union agent. Roger and his allies form an uneasy alliance with Vera to prevent something terrible from happening.

Alan releases Beck from prison and orders him to rebuild the Big Fau. Roger attempts to track down Angel, who holds a dark secret.

A newly rebuilt Big Duo reappears and controlled by Alan. Roger opposed it in the Big O as a huge fight breaks out.

All out war begins as Union bombards the city with beams of light. Angel and Roger go to face Vera, who reveals the shocking truth about what happened forty years ago.

The police and every other survivor watch as the Big O and Big Fau begin their final clash. Who will be the ultimate victor and what will become of the city and all of its people?