Pete identifies the figure as the Iron Shadow, the "most awesome superhero of the Silver Age of comics." Pete explains that in the comics, he's a non-powered superhero, an urban vigilante. Pete and Myka confront Sheldon at his apartment. He finally admits that he has an artifact and they warn him that it could go out of control.
Sheldon snaps when they mention Loretta, and he breaks a mug. When they ask for the artifact, he seemingly agrees and goes to get it from his bedroom. The building shakes and they run into the room to discover that he's flown out the window. They run to the street and spot the Iron Shadow on a nearby rooftop, glowing with gravitational force. He fires a blast of the force at them, warns them to get out of "his" city, and leaps away. Myka realizes that Sheldon is using the power to alter his density.
At the diner, Sheldon comes to see Loretta and asks if she feels safer. Loretta assures him that she always feels safe with him. Sheldon says that things are different and that he's doing everything for her. He then shows her the Iron Shadow mask and explains that he's the vigilante. Pete and Myka barge in and call on him to surrender. He activates the artifact, increasing his mass. However, it starts to go out of control. A shelf almost falls on Loretta but Pete dives into her to push her out of the way and Sheldon leaps away before he can do any more damage.
The agents make sure that Loretta is alive and explain to her that Sheldon is doing it for her out of love. Claudia calls and tells them that she has what they need to stop the belt, and arrives at the diner. She has a suit that absorbs kinetic energy and gauntlets that redirects the force. Loretta tells them he is probably at the automotive factory where he was laid off. Pete and Claudia go to find him there, and he blames them for harming Loretta. Claudia warns that the gravitational waves he's generating will soon destroy the city, and they call in Myka donning the suit and gauntlets. She tries to get close to him, insisting that they want to help him. He takes her hand and she absorbs the kinetic energy of the gravitational waves. Pete runs in and removes the belt, and Myka releases the energy through the gauntlets and up into the sky, dissipating it harmlessly.
Loretta arrives and assures him that everything is okay and they have the belt. However, they realize that the belt isn't the artifact. They realize that the trunks are the artifact. They activate again and Pete pulls Loretta to safety. Sheldon's density increases to the point of infinite mass, and Claudia warns it will take the city with him. She tells Myka to siphon as much energy from him as possible and get the trunks off of him. Myka lets herself be pulled toward Sheldon and absorbs more energy, but she becomes locked in the power circuit. Pete runs over and pulls the trunks off and the gravitational collapse ceases. Claudia neutralizes the trunks while Loretta and Sheldon kiss.
Later, Sheldon explains that he found the trunks at a yard sale. He offers to turn himself in for his crimes, but Pete says it isn't necessary. Claudia wonders why they're letting him go, and Myka explains that Sheldon wasn't in control of himself, and they should forgive him because an artifact was responsible.
Sheldon is portrayed by Sean Maher, and his girlfriend, Loretta, is portrayed by Jewel Staite, who both played main characters in the popular, but short-lived, television series Firefly. They portrayed the characters of Simon Tam and Kaylee Frye, also a romantic couple.