It's part of the Shadowline shared universe, set in a world where a second, hidden race - the Shadow Dwellers - evolved alongside humanity. Individually, Shadow Dwellers are more powerful than humans, but humans vastly outnumber them and so they've tended to stay hidden.
Victor Guillermos and Lenore Castle are the titular Power Line duo, two young Shadow Dwellers who grew up with minor powers. Victor has a weak force field; Lenore can defy gravity for leaps that are almost - but not quite - flight. However, when they're together, their powers seem to be supercharged.
They have also made enemies of the Ravenscores, a powerful Shadow Dweller family who have killed Victor's parents and Lenore's mother.
Encouraged by Victor's uncle Ripley, the two decide to become superheroes, to help humans and Shadow Dwellers alike - and, somehow, to find a way to avenge their families.
After the series was cancelled, Victor and Lenore's story continued in Critical Mass, an Anthology Comic combining the previous three Shadowline titles.
Power Line includes the following tropes:
- An Arm and a Leg: Uncle Ripley's gift allows him to transmute his hands to metal. Eric Ravenscore deals with this by severing his right hand at the wrist.
- Arranged Marriage: Lenore's parents are keen to arrange a marriage with Eric Ravenscore. Lenore seems happy to oblige, until he shows his true colors.
- Barrier Warrior: Victor's default power is a weak force field. It's just about able to deflect a glancing blow from a punch or a knife, but not much more.
- Big Bad: Eric Ravenscore, who sets the plot in motion by maiming Ripley, killing the rest of Victor's family, killing Lenore's mother and kidnapping her father.
- Not Quite Flight: Lenore's default power. It looks very impressive when she leaps into the air, but she can't stay aloft for more than a few seconds.
- Role Reversal: When Victor and Lenore first started out as the Power Line, Victor was gung-ho about being a superhero, and Lenore was reluctant to be one. At the end of Critical Mass, Victor wishes to retire, but Lenore has become dedicated to the Power Line continuing on.
- Self-Made Orphan: Eric needs a scapegoat for Lenore and Victor's escape and decides that his own father, Tyler, is no longer useful enough to live.
- Thinking Up Portals: Tyler Ravenscore develops a version of this power shortly before the start of the series, allowing him to act as a living Trojan Horse. When Victor's family invite him in alone to discuss peace, he becomes a living gateway for the Ravenscore's killers to travel through.
