The parasites live in Hell's Heart, the slums of Washington DC, a neighborhood in such bad that the police and government have given up on trying to fix it. The sad and hopeless people of Hell's Heart are easy targets for these monsters, bringing the neighborhood down even further. Only Traci Thirteen and Superman can see the parasites in their physical forms.

When Lana Lang ventures into Hell's Heart to help Traci Thirteen find her father, she becomes another victim of the Heartbreakers. She loses her memory and all control of herself, wanting to be loved and cared for. One of the parasites also attach themselves to Superman, draining his will to help people. Doctor Thirteen, another victim, believes that his daughter's magic is to blame for the death of his wife and attempts to kill Traci Thirteen.

Superman discovers that only good memories that fill people with hope can help the victims defeat the parasites. Superman and Lana free themselves with memories of their childhoods in Smallville. Doctor Thirteen is saved when Superman convinces him that he loves his daughter and asks him to remember when she was a child.