The forth episode of the anime Big O. The previous episode was Electric City.

The episode opens with Roger persuading an elderly woman to give up her apartment in a decaying tenement. The pleased landlord informs Roger that his parent company might want to hire the negotiator.

In Paradigm City, "Parent Company" always means the same thing: the Paradigm Group, the management corporation that runs almost every aspect of Paradigm City. Roger visits the Group's headquarters, and is surprised to see Angel there. This time she's posing as Patricia Lovejoy, the secretary of Paradigm Press chief Phil Gassé. On the elevator ride up to the Press' offices, sparks fly between the pair-- and they get a glimpse of Alex Rosewater, the mysterious CEO of the Paradigm Group.

Roger is hired to go and seek out a missing reporter, a certain Michael Seebach. Paradigm Press desperately wants a certain manuscript for him, but the reporter seems to have gone into hiding. With some timely (if grumpy) assistance from Dan Dastun, Roger finds a spare apartment in Seebach's name-- and barely escapes as the place erupts in flames.

"You!" a voice booms from the building top. "You are a corrupt dog-- on the city's leash!" Roger looks up to see a ragged man, swathed in bandages. When asked if he's Michael Seebach, the man sniggers and declares that Seebach no longer exists-- his name is Schwarzwald ("Black Forest"). Before Roger can get his bearings, the man is gone.

All of this digging for other people's mysteries prompts Roger to finally explore some mysteries of his own-- namely, the nature of the underground transit system that shuttles the Big O around the city. After exploring the tunnels, Roger finds a way down to a lower level-- and as he descends further, the terrain and structures seem newer and newer. As he's climbing down a huge ladder, he's suddenly seized by irrational, uncontrollable, pure terror-- he loses his grip and falls to the floor.

He wakes with his head cradled in Dorothy's lap. He initially mistakes her for his mother, which causes him considerable consternation. Dorothy seems puzzled by his fear (now vanished), and the two probe further into the tunnels.

They come across a ruined minature city, with what appears to be a Megadeus prototype sprawled in front of it. As they approach, Schwarzwald appears, commenting that he's surprised that Roger made it so far. As Schwarzwald prepares to attack, Dorothy suddenly charges forward, emitting a high-speed burst of communication to the giant robot-- which promptly wakes up.

Dorothy is suddenly siezed by the same terror that plagued Roger before. "This robot shouldn't exist!" she yells fearfully, "It is not like me at all!" Roger summons the Big O, which surprises the hell out of Schwarzwald, who's already shaken by the unexpected awakening of the other giant robot. After an intense battle with the physically stronger robot, Roger uses the Big O's chest missiles to destroy it. But Schwarzwald has disappeared...

The next episode is Bring Back My Ghost.