Robert Crane is a scientist whose brain is placed inside a robotic body after he had been fatally shot by a criminal named Mason.

He assumes the civilian identity of Paul Dennis and joins the All-Star Squadron, accompanied by the robotic dog Robbie.

Despite this, the story remains grounded in Robotman's struggle to adjust to his new existence, at one point having to reveal his real identity in court, and being declared legally human.

Robotman was revealed to have been one of several other heroes involved in the first meeting of the charter members of the Justice League of America prior to the official forming of the team, an event which was suppressed from the public record.

The series depicts that after World War II Robotman purposefully ignores his humanity, developing an inhuman mental state, focusing on being a robot.

He is depicted stopping a robbery with deadly force, and later being approached by Tex Thompson (Mr. America), the current form of the Ultra-Humanite.

While the other heroes face Dynaman, a transformed Dan the Dyna-Mite, Paula Brooks (a reformed villain, the Tigress) and Lance Gallant (Captain Triumph), who had become lovers over the course of the story, confront and defeat Robotman.

In the end, Gallant, refusing to transform into Captain Triumph, shoves one of the Tigress' wooden crossbow bolts further into Robotman's head.